[S390] Use generic bug.

Generic bug implementation for s390. Will increase the value of the
console output on BUG() statements since registers r0-r5,r14 will
not be clobbered by a printk() call that was previously done before
the illegal instruction of BUG() was hit.
Also implements an architecture specific WARN_ON(). Output of that
could be increased but requires common code change.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 0f293aa..0f9517b 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -41,6 +41,11 @@
 config GENERIC_TIME
 	def_bool y
 
+config GENERIC_BUG
+	bool
+	depends on BUG
+	default y
+
 config NO_IOMEM
 	def_bool y