kbuild: fix O=.. build with arm

With a make O=... build kbuild would only create
the include2/asm symlink for archs that not yet
had moved headers to include/$ARCH/include

There is no longer any reason to avoid the symlink
for archs that has moved their headers so create it
unconditionally.

This fixes arm because kbuild checked for include/asm-$ARCH/errno.h
and that file was not present for arm but the platform files
are not yet moved.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Russell King <rmk@arm.linux.org.uk>

Makefile

@@ -929,8 +929,8 @@ ifneq ($(KBUILD_SRC),)
 		echo "  in the '$(srctree)' directory.";\
 		/bin/false; \
 	fi;
-	$(Q)if [ ! -d include2 ]; then mkdir -p include2; fi;
+	$(Q)if [ ! -d include2 ]; then                                  \
-	$(Q)if [ -e $(srctree)/include/asm-$(SRCARCH)/errno.h ]; then  \
+	    mkdir -p include2;                                          \
 	    ln -fsn $(srctree)/include/asm-$(SRCARCH) include2/asm;     \
 	fi
 endif