lib: Add missing arch generic-y entries for asm-generic/hash.h

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/arch/s390/include/asm/Kbuild b/arch/s390/include/asm/Kbuild
index 7a5288f..8386a4a 100644
--- a/arch/s390/include/asm/Kbuild
+++ b/arch/s390/include/asm/Kbuild
@@ -3,3 +3,4 @@
 generic-y += clkdev.h
 generic-y += trace_clock.h
 generic-y += preempt.h
+generic-y += hash.h