[S390] Avoid sparse warnings.

Monthly sparse warning avoidance patch. Sigh.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
diff --git a/include/asm-s390/ipl.h b/include/asm-s390/ipl.h
index bdcd448..2c40fd3 100644
--- a/include/asm-s390/ipl.h
+++ b/include/asm-s390/ipl.h
@@ -79,8 +79,8 @@
  * IPL validity flags
  */
 extern u32 ipl_flags;
-
 extern u32 dump_prefix_page;
+extern unsigned int zfcpdump_prefix_array[];
 
 extern void do_reipl(void);
 extern void ipl_save_parameters(void);