[S390] add __ucmpdi2() helper function

Provide __ucmpdi2() helper function on 31 bit so we don't run
again and again in compile errors like this one:

kernel/built-in.o: In function `T.689':
perf_counter.c:(.text+0x56c86): undefined reference to `__ucmpdi2'

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/lib/Makefile b/arch/s390/lib/Makefile
index ab6735d..97975ec 100644
--- a/arch/s390/lib/Makefile
+++ b/arch/s390/lib/Makefile
@@ -3,6 +3,6 @@
 #
 
 lib-y += delay.o string.o uaccess_std.o uaccess_pt.o
-obj-$(CONFIG_32BIT) += div64.o qrnnd.o
+obj-$(CONFIG_32BIT) += div64.o qrnnd.o ucmpdi2.o
 lib-$(CONFIG_64BIT) += uaccess_mvcos.o
 lib-$(CONFIG_SMP) += spinlock.o