This reverts the following two commits:
- a555bdd0c5 ("Kbuild: enable TRIM_UNUSED_KSYMS again, with some guarding")
- 5cf0fd591f ("Kbuild: disable TRIM_UNUSED_KSYMS option")
Commit 5e9e95cc91 ("kbuild: implement CONFIG_TRIM_UNUSED_KSYMS without
recursion") solved the build time issue.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>