iommu/vt-d: Increase buffer size for device name

GCC is not happy with the current code, e.g.:

.../iommu/intel/dmar.c:1063:9: note: ‘sprintf’ output between 6 and 15 bytes into a destination of size 13
 1063 |         sprintf(iommu->name, "dmar%d", iommu->seq_id);

When `make W=1` is supplied, this prevents kernel building. Fix it by
increasing the buffer size for device name and use sizeoF() instead of
hard coded constants.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20241014104529.4025937-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

Author: andy-shev

drivers/iommu/intel/dmar.c

@@ -1060,7 +1060,7 @@ static int alloc_iommu(struct dmar_drhd_unit *drhd)
 		err = iommu->seq_id;
 		goto error;
 	}
-	sprintf(iommu->name, "dmar%d", iommu->seq_id);
+	snprintf(iommu->name, sizeof(iommu->name), "dmar%d", iommu->seq_id);
 
 	err = map_iommu(iommu, drhd);
 	if (err) {

drivers/iommu/intel/iommu.h

@@ -720,7 +720,7 @@ struct intel_iommu {
 	int		msagaw; /* max sagaw of this iommu */
 	unsigned int	irq, pr_irq, perf_irq;
 	u16		segment;     /* PCI segment# */
-	unsigned char 	name[13];    /* Device Name */
+	unsigned char	name[16];    /* Device Name */
 
 #ifdef CONFIG_INTEL_IOMMU
 	unsigned long 	*domain_ids; /* bitmap of domains */