s390: reenable gcc plugins for real

Martin's patch 6eedfaac ("s390: reenable gcc plugins") was lost in
the merge commit 85a0b791 ("Merge branch 'for-linus' of
git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux") therefore
let's enable gcc plugins again.

Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

arch/s390/Kconfig

@@ -139,7 +139,7 @@ config S390
 	select HAVE_FUNCTION_GRAPH_TRACER
 	select HAVE_FUNCTION_TRACER
 	select HAVE_FUTEX_CMPXCHG if FUTEX
-	select HAVE_GCC_PLUGINS if BROKEN
+	select HAVE_GCC_PLUGINS
 	select HAVE_KERNEL_BZIP2
 	select HAVE_KERNEL_GZIP
 	select HAVE_KERNEL_LZ4