kbuild: do not warn about __*init/__*exit symbols being exported

We have several legitimate uses where we export symbols
annotated with one of:
__devinit, __cpuinit, __meminit and their exit counterpart.
So let's stop warning about those being exported in favour
of adding all sorts of workaround to silence the warning.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

scripts/mod/modpost.c

@@ -870,7 +870,7 @@ const struct sectioncheck sectioncheck[] = {
 /* Do not export init/exit functions or data */
 {
 	.fromsec = { "__ksymtab*", NULL },
-	.tosec   = { ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL },
+	.tosec   = { INIT_SECTIONS, EXIT_SECTIONS, NULL },
 	.mismatch = EXPORT_TO_INIT_EXIT
 }
 };