IB/hf1: Use string_upper() instead of an open coded variant

Use string_upper() from the string helper module instead of an	open coded
variant.

Link: https://lore.kernel.org/r/20211001123153.67379-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/hw/hfi1/efivar.c

@@ -3,7 +3,9 @@
  * Copyright(c) 2015, 2016 Intel Corporation.
  */
 
-#include <linux/ctype.h>
+#include <linux/string.h>
+#include <linux/string_helpers.h>
+
 #include "efivar.h"
 
 /* GUID for HFI1 variables in EFI */
@@ -112,7 +114,6 @@ int read_hfi1_efi_var(struct hfi1_devdata *dd, const char *kind,
 	char prefix_name[64];
 	char name[64];
 	int result;
-	int i;
 
 	/* create a common prefix */
 	snprintf(prefix_name, sizeof(prefix_name), "%04x:%02x:%02x.%x",
@@ -128,10 +129,7 @@ int read_hfi1_efi_var(struct hfi1_devdata *dd, const char *kind,
 	 * variable.
 	 */
 	if (result) {
-		/* Converting to uppercase */
-		for (i = 0; prefix_name[i]; i++)
-			if (isalpha(prefix_name[i]))
-				prefix_name[i] = toupper(prefix_name[i]);
+		string_upper(prefix_name, prefix_name);
 		snprintf(name, sizeof(name), "%s-%s", prefix_name, kind);
 		result = read_efi_var(name, size, return_data);
 	}