kbuild: do not do section mismatch checks on vmlinux in 2nd pass

We already check and warn about section mismatches from vmlinux
(build as vmlinux.o) during first pass so skip the checks
during the 2nd pass where we process modules.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

diff --cc scripts/Makefile.modpost
Simple merge

diff --cc scripts/mod/modpost.c
Simple merge