s390/dasd: Fix potential memleak in dasd_eckd_init()

`dasd_reserve_req` is allocated before `dasd_vol_info_req`, and it
also needs to be freed before the error returns, just like the other
cases in this function.

Fixes: 9e12e54c ("s390/dasd: Handle out-of-space constraint")
Signed-off-by: Qiheng Lin <linqiheng@huawei.com>
Link: https://lore.kernel.org/r/20221208133809.16796-1-linqiheng@huawei.comSigned-off-by: Stefan Haberland <sth@linux.ibm.com>
Link: https://lore.kernel.org/r/20230210000253.1644903-3-sth@linux.ibm.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

drivers/s390/block/dasd_eckd.c

@@ -6954,8 +6954,10 @@ dasd_eckd_init(void)
 		return -ENOMEM;
 	dasd_vol_info_req = kmalloc(sizeof(*dasd_vol_info_req),
 				    GFP_KERNEL | GFP_DMA);
-	if (!dasd_vol_info_req)
+	if (!dasd_vol_info_req) {
+		kfree(dasd_reserve_req);
 		return -ENOMEM;
+	}
 	pe_handler_worker = kmalloc(sizeof(*pe_handler_worker),
 				    GFP_KERNEL | GFP_DMA);
 	if (!pe_handler_worker) {