Staging: xgifb: Fix NULL pointer comparison warning

Replace direct comparisons to NULL i.e.
'x == NULL' with '!x'.
This problem was detected by checkpatch.
Signed-off-by: Maninder Singh <maninder.s2@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/xgifb/XGI_main_26.c

@@ -518,7 +518,7 @@ static void XGIfb_search_crt2type(const char *name)
 {
 	int i = 0;
 
-	if (name == NULL)
+	if (!name)
 		return;
 
 	while (XGI_crt2type[i].type_no != -1) {
@@ -589,7 +589,7 @@ static void XGIfb_search_tvstd(const char *name)
 {
 	int i = 0;
 
-	if (name == NULL)
+	if (!name)
 		return;
 
 	while (XGI_tvtype[i].type_no != -1) {