kbuild: rebuild GCC plugins when the compiler is upgraded

Linus reported a build error due to the GCC plugin incompatibility
when the compiler is upgraded. [1]

GCC plugins are tied to a particular GCC version. So, they must be
rebuilt when the compiler is upgraded.

This seems to be a long-standing flaw since the initial support of
GCC plugins.

Extend commit 8b59cd81dc ("kbuild: ensure full rebuild when the
compiler is updated"), so that GCC plugins are covered by the
compiler upgrade detection.

[1]: https://lore.kernel.org/lkml/CAHk-=wieoN5ttOy7SnsGwZv+Fni3R6m-Ut=oxih6bbZ28G+4dw@mail.gmail.com/

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>

init/Kconfig

@@ -20,10 +20,10 @@ config CC_VERSION_TEXT
 	    When the compiler is updated, Kconfig will be invoked.
 
 	  - Ensure full rebuild when the compiler is updated
-	    include/linux/kconfig.h contains this option in the comment line so
-	    fixdep adds include/config/cc/version/text.h into the auto-generated
-	    dependency. When the compiler is updated, syncconfig will touch it
-	    and then every file will be rebuilt.
+	    include/linux/compiler-version.h contains this option in the comment
+	    line so fixdep adds include/config/cc/version/text.h into the
+	    auto-generated dependency. When the compiler is updated, syncconfig
+	    will touch it and then every file will be rebuilt.
 
 config CC_IS_GCC
 	def_bool $(success,test "$(cc-name)" = GCC)