s390/cio: 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: https://github.com/KSPP/linux/issues/78
Link: https://gcc.gnu.org/pipermail/gcc-patches/2022-October/602902.htmlSigned-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

drivers/s390/cio/chsc.c

@@ -1171,7 +1171,7 @@ int __init chsc_get_cssid_iid(int idx, u8 *cssid, u8 *iid)
 			u8 cssid;
 			u8 iid;
 			u32 : 16;
-		} list[0];
+		} list[];
 	} *sdcal_area;
 	int ret;
 

drivers/s390/cio/chsc.h

@@ -120,7 +120,7 @@ struct chsc_scpd {
 	u32 zeroes1;
 	struct chsc_header response;
 	u32:32;
-	u8 data[0];
+	u8 data[];
 } __packed __aligned(PAGE_SIZE);
 
 struct chsc_sda_area {