cmd/led.c: Remove unnecessary check on 'cmd' value

We first check that if argc is less than 2 we return CMD_RET_USAGE.  We
then see if argc is greater than 2 and if so call get_led_cmd() to set
'cmd' and otherwise set it to LEDST_COUNT (which will always be positive
as it's an enum with 0 already assigned).  Therefore the test on if cmd
is less than 0 will always be false and simply be omitted.  Reported by
clang-3.8.

Signed-off-by: Tom Rini <trini@konsulko.com>

cmd/led.c

@@ -90,8 +90,6 @@ int do_led(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 		return list_leds();
 
 	cmd = argc > 2 ? get_led_cmd(argv[2]) : LEDST_COUNT;
-	if (cmd < 0)
-		return CMD_RET_USAGE;
 #ifdef CONFIG_LED_BLINK
 	if (cmd == LEDST_BLINK) {
 		if (argc < 4)