LoongArch: BPF: Support mixing bpf2bpf and tailcalls

The current implementation already allow such mixing.
Let's enable it in JIT.

Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
Link: https://lore.kernel.org/r/20230218105317.4139666-1-hengqi.chen@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

arch/loongarch/net/bpf_jit.c

@@ -1248,3 +1248,9 @@ out:
 
 	return prog;
 }
+
+/* Indicate the JIT backend supports mixing bpf2bpf and tailcalls. */
+bool bpf_jit_supports_subprog_tailcalls(void)
+{
+	return true;
+}