test/cuse: fix ns_dev format truncation

gcc 12 assumes that nsid might take value of UINT32_MAX,
which when represented as a string does not fit in ns_dev.

This is fixed by accomodating the UINT32_MAX string representation
and the 'n' character.

Following error was shown before this patch:
cuse.c: In function ‘verify_devices’:
cuse.c:133:42: error: ‘snprintf’ output may be truncated before the last format character [-Werror=format-truncation=]
133 |         snprintf(ns_dev, sizeof(ns_dev), "%sn%" PRIu32, ctrlr_dev, nsid);
  |                                          ^~~~~~
In file included from /home/tzawadzk/spdk/include/spdk/stdinc.h:23,
	     from /home/tzawadzk/spdk/test/spdk_cunit.h:9,
	     from cuse.c:7:
/usr/include/inttypes.h:104:27: note: format string is defined here
104 | # define PRIu32         "u"
  |                           ^
cuse.c:133:9: note: ‘snprintf’ output between 3 and 267 bytes into a destination of size 266
133 |         snprintf(ns_dev, sizeof(ns_dev), "%sn%" PRIu32, ctrlr_dev, nsid);
  |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Tomasz Zawadzki <tomasz.zawadzki@intel.com>
Change-Id: I14e058edc780d33abdd5eb6ce5ab47ac5d18f10a
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/13412
Community-CI: Broadcom CI <spdk-ci.pdl@broadcom.com>
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Konrad Sztyber <konrad.sztyber@intel.com>
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>

test/nvme/cuse/cuse.c

@@ -106,7 +106,8 @@ verify_devices(struct spdk_nvme_ctrlr *ctrlr)
 {
 	char ctrlr_name[256];
 	size_t ctrlr_name_size;
-	char ctrlr_dev[256], ns_dev[256 + 10];
+	char ctrlr_dev[256];
+	char ns_dev[256 + 1 + 10]; /* sizeof ctrl_dev + 'n' + string size of UINT32_MAX */
 	uint32_t nsid, num_ns;
 	int rv;