ice: Use pci_get_dsn()

Replace the open-coded implementation for reading the PCIe DSN with
pci_get_dsn().

The pci_get_dsn() function will perform two pci_read_config_dword calls
to read the lower and upper config dwords. It bitwise ORs them into
a u64 value. Instead of using put_unaligned_le32 to convert the value to
LE32 format, just use the %016llX printf specifier. This will print the
u64 correct, putting the most significant byte of the value first. Since
pci_get_dsn() correctly orders the two dwords into a u64, this should
produce equivalent results in less code.
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/intel/ice/ice_main.c

@@ -3087,30 +3087,22 @@ static char *ice_get_opt_fw_name(struct ice_pf *pf)
 	 * followed by a EUI-64 identifier (PCIe Device Serial Number)
 	 */
 	struct pci_dev *pdev = pf->pdev;
-	char *opt_fw_filename = NULL;
-	u32 dword;
-	u8 dsn[8];
-	int pos;
+	char *opt_fw_filename;
+	u64 dsn;
 
 	/* Determine the name of the optional file using the DSN (two
 	 * dwords following the start of the DSN Capability).
 	 */
-	pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_DSN);
-	if (pos) {
-		opt_fw_filename = kzalloc(NAME_MAX, GFP_KERNEL);
-		if (!opt_fw_filename)
-			return NULL;
-
-		pci_read_config_dword(pdev, pos + 4, &dword);
-		put_unaligned_le32(dword, &dsn[0]);
-		pci_read_config_dword(pdev, pos + 8, &dword);
-		put_unaligned_le32(dword, &dsn[4]);
-		snprintf(opt_fw_filename, NAME_MAX,
-			 "%sice-%02x%02x%02x%02x%02x%02x%02x%02x.pkg",
-			 ICE_DDP_PKG_PATH,
-			 dsn[7], dsn[6], dsn[5], dsn[4],
-			 dsn[3], dsn[2], dsn[1], dsn[0]);
-	}
+	dsn = pci_get_dsn(pdev);
+	if (!dsn)
+		return NULL;
+
+	opt_fw_filename = kzalloc(NAME_MAX, GFP_KERNEL);
+	if (!opt_fw_filename)
+		return NULL;
+
+	snprintf(opt_fw_filename, NAME_MAX, "%sice-%016llX.pkg",
+		 ICE_DDP_PKG_PATH, dsn);
 
 	return opt_fw_filename;
 }