usb: gadget: Remove the LUN checks which are always true

Comparing an unsigned integer with greater than or equal to zero is
always true.  So, it is safe to remove similar checks from
'f_mass_storage.c' and 'file_storage.c'

Signed-off-by: Maxin B. John <maxin.john@gmail.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/gadget/f_mass_storage.c

@@ -1884,7 +1884,7 @@ static int check_command(struct fsg_common *common, int cmnd_size,
 		    common->lun, lun);
 
 	/* Check the LUN */
-	if (common->lun >= 0 && common->lun < common->nluns) {
+	if (common->lun < common->nluns) {
 		curlun = &common->luns[common->lun];
 		common->curlun = curlun;
 		if (common->cmnd[0] != REQUEST_SENSE) {

drivers/usb/gadget/file_storage.c

@@ -2285,7 +2285,7 @@ static int check_command(struct fsg_dev *fsg, int cmnd_size,
 		fsg->lun = lun;		// Use LUN from the command
 
 	/* Check the LUN */
-	if (fsg->lun >= 0 && fsg->lun < fsg->nluns) {
+	if (fsg->lun < fsg->nluns) {
 		fsg->curlun = curlun = &fsg->luns[fsg->lun];
 		if (fsg->cmnd[0] != REQUEST_SENSE) {
 			curlun->sense_data = SS_NO_SENSE;