bpf, doc: add bpf list as secondary entry to maintainers file

We recently created a bpf@vger.kernel.org list (https://lore.kernel.org/bpf/)
for BPF related discussions, originally in context of BPF track at LSF/MM
for topic discussions. It's *optional* but *desirable* to keep it in Cc for
BPF related kernel/loader/llvm/tooling threads, meaning also infrastructure
like llvm that sits on top of kernel but is crucial to BPF. In any case,
netdev with it's bpf delegate is *as-is* today primary list for patches, so
nothing changes in the workflow. Main purpose is to have some more awareness
for the bpf@vger.kernel.org list that folks can Cc for BPF specific topics.

Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

MAINTAINERS

@@ -2852,7 +2852,7 @@ R:	Martin KaFai Lau <kafai@fb.com>
 R:	Song Liu <songliubraving@fb.com>
 R:	Yonghong Song <yhs@fb.com>
 L:	netdev@vger.kernel.org
-L:	linux-kernel@vger.kernel.org
+L:	bpf@vger.kernel.org
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git
 Q:	https://patchwork.ozlabs.org/project/netdev/list/?delegate=77147
@@ -2882,6 +2882,7 @@ N:	bpf
 BPF JIT for ARM
 M:	Shubham Bansal <illusionist.neo@gmail.com>
 L:	netdev@vger.kernel.org
+L:	bpf@vger.kernel.org
 S:	Maintained
 F:	arch/arm/net/
 
@@ -2890,18 +2891,21 @@ M:	Daniel Borkmann <daniel@iogearbox.net>
 M:	Alexei Starovoitov <ast@kernel.org>
 M:	Zi Shen Lim <zlim.lnx@gmail.com>
 L:	netdev@vger.kernel.org
+L:	bpf@vger.kernel.org
 S:	Supported
 F:	arch/arm64/net/
 
 BPF JIT for MIPS (32-BIT AND 64-BIT)
 M:	Paul Burton <paul.burton@mips.com>
 L:	netdev@vger.kernel.org
+L:	bpf@vger.kernel.org
 S:	Maintained
 F:	arch/mips/net/
 
 BPF JIT for NFP NICs
 M:	Jakub Kicinski <jakub.kicinski@netronome.com>
 L:	netdev@vger.kernel.org
+L:	bpf@vger.kernel.org
 S:	Supported
 F:	drivers/net/ethernet/netronome/nfp/bpf/
 
@@ -2909,6 +2913,7 @@ BPF JIT for POWERPC (32-BIT AND 64-BIT)
 M:	Naveen N. Rao <naveen.n.rao@linux.ibm.com>
 M:	Sandipan Das <sandipan@linux.ibm.com>
 L:	netdev@vger.kernel.org
+L:	bpf@vger.kernel.org
 S:	Maintained
 F:	arch/powerpc/net/
 
@@ -2916,6 +2921,7 @@ BPF JIT for S390
 M:	Martin Schwidefsky <schwidefsky@de.ibm.com>
 M:	Heiko Carstens <heiko.carstens@de.ibm.com>
 L:	netdev@vger.kernel.org
+L:	bpf@vger.kernel.org
 S:	Maintained
 F:	arch/s390/net/
 X:	arch/s390/net/pnet.c
@@ -2923,12 +2929,14 @@ X:	arch/s390/net/pnet.c
 BPF JIT for SPARC (32-BIT AND 64-BIT)
 M:	David S. Miller <davem@davemloft.net>
 L:	netdev@vger.kernel.org
+L:	bpf@vger.kernel.org
 S:	Maintained
 F:	arch/sparc/net/
 
 BPF JIT for X86 32-BIT
 M:	Wang YanQing <udknight@gmail.com>
 L:	netdev@vger.kernel.org
+L:	bpf@vger.kernel.org
 S:	Maintained
 F:	arch/x86/net/bpf_jit_comp32.c
 
@@ -2936,6 +2944,7 @@ BPF JIT for X86 64-BIT
 M:	Alexei Starovoitov <ast@kernel.org>
 M:	Daniel Borkmann <daniel@iogearbox.net>
 L:	netdev@vger.kernel.org
+L:	bpf@vger.kernel.org
 S:	Supported
 F:	arch/x86/net/
 X:	arch/x86/net/bpf_jit_comp32.c
@@ -8487,6 +8496,7 @@ L7 BPF FRAMEWORK
 M:	John Fastabend <john.fastabend@gmail.com>
 M:	Daniel Borkmann <daniel@iogearbox.net>
 L:	netdev@vger.kernel.org
+L:	bpf@vger.kernel.org
 S:	Maintained
 F:	include/linux/skmsg.h
 F:	net/core/skmsg.c
@@ -16714,6 +16724,7 @@ M:	Jesper Dangaard Brouer <hawk@kernel.org>
 M:	John Fastabend <john.fastabend@gmail.com>
 L:	netdev@vger.kernel.org
 L:	xdp-newbies@vger.kernel.org
+L:	bpf@vger.kernel.org
 S:	Supported
 F:	net/core/xdp.c
 F:	include/net/xdp.h
@@ -16727,6 +16738,7 @@ XDP SOCKETS (AF_XDP)
 M:	Björn Töpel <bjorn.topel@intel.com>
 M:	Magnus Karlsson <magnus.karlsson@intel.com>
 L:	netdev@vger.kernel.org
+L:	bpf@vger.kernel.org
 S:	Maintained
 F:	kernel/bpf/xskmap.c
 F:	net/xdp/