kbuild: fixdep: Resync this with v4.17

kbuild: fixdep: Resync this with v4.17

The previous kbuild resync of e91610da7c8a ("kconfig: re-sync with Linux
4.17-rc4") accidentally did not sync the fixdep program.  This commit
brings fixdep in line with the rest of that previous resync.

This includes all of the following Linux kernel commits:
fbfa9be9904e kbuild: move include/config/ksym/* to include/ksym/*
5b8ad96d1a44 fixdep: remove some false CONFIG_ matches
14a596a7e6fd fixdep: remove stale references to uml-config.h
ab9ce9feed36 fixdep: use existing helper to check modular CONFIG options
87b95a81357d fixdep: refactor parse_dep_file()
5d1ef76f5a22 fixdep: move global variables to local variables of main()
ccfe78873c22 fixdep: remove unneeded memcpy() in parse_dep_file()
4003fd80cba9 fixdep: factor out common code for reading files
01b5cbe7012f fixdep: use malloc() and read() to load dep_file to buffer
41f92cffba19 fixdep: remove unnecessary <arpa/inet.h> inclusion
7c2ec43a2154 fixdep: exit with error code in error branches of do_config_file()
4e433fc4d1a9 fixdep: trivial: typo fix and correction
dee81e988674 fixdep: faster CONFIG_ search
c1a95fda2a40 kbuild: add fine grained build dependencies for exported symbols
d8329e35cc08 fixdep: accept extra dependencies on stdin
4c835b57b8de fixdep: constify strrcmp arguments

Of note is that when applying dee81e988674 above our logic in that area
required some careful consideration to continue to apply.

[Fold in bugfix to allow us to include 638e69cf2230 from upstream]
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
[Merge everything to U-Boot, rework dee81e988674]
Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Masahiro Yamada <masahiroy@kernel.org>