kbuild: warn about references from .init.text to .exit.text

The .exit.text section may be discarded either at build or at runtime.
So let modpost warn if this situation is detected.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

scripts/mod/modpost.c

@@ -1214,7 +1214,6 @@ static int exit_section_ref_ok(const char *name)
 		".exit.data",
 		".exit.text",
 		".exitcall.exit",
-		".init.text",
 		".rodata",
 		NULL
 	};