modpost: Optimize symbol search from linear to binary search

modpost: Optimize symbol search from linear to binary search

[ Upstream commit 4074532758c5c367d3fcb8d124150824a254659d ]

Modify modpost to use binary search for converting addresses back
into symbol references.  Previously it used linear search.

This change saves a few seconds of wall time for defconfig builds,
but can save several minutes on allyesconfigs.

Before:
$ make LLVM=1 -j128 allyesconfig vmlinux -s KCFLAGS="-Wno-error"
$ time scripts/mod/modpost -M -m -a -N -o vmlinux.symvers vmlinux.o
198.38user 1.27system 3:19.71elapsed

After:
$ make LLVM=1 -j128 allyesconfig vmlinux -s KCFLAGS="-Wno-error"
$ time scripts/mod/modpost -M -m -a -N -o vmlinux.symvers vmlinux.o
11.91user 0.85system 0:12.78elapsed

Signed-off-by: Jack Brennen <jbrennen@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Stable-dep-of: 1102f9f85bf6 ("modpost: do not make find_tosym() return NULL")
Signed-off-by: Sasha Levin <sashal@kernel.org>