s390/sclp: replace zero-length array with flexible-array member

There are numerous patches which convert zero-length arrays with a
flexible-array member. Convert the remaining s390 occurrences.

Suggested-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: KSPP#78
Link: https://gcc.gnu.org/pipermail/gcc-patches/2022-October/602902.html
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

Author: hcahca

drivers/s390/char/sclp.h

@@ -204,7 +204,7 @@ struct read_storage_sccb {
 	u16 assigned;
 	u16 standby;
 	u16 :16;
-	u32 entries[0];
+	u32 entries[];
 } __packed;
 
 static inline void sclp_fill_core_info(struct sclp_core_info *info,

drivers/s390/char/sclp_cmd.c

@@ -241,7 +241,7 @@ struct attach_storage_sccb {
 	u16 :16;
 	u16 assigned;
 	u32 :32;
-	u32 entries[0];
+	u32 entries[];
 } __packed;
 
 static int sclp_attach_storage(u8 id)