pcs440ep: Clean up led command definition

The pcs440ep's led command usage formatting is non-standard.  It
was made standard in preparation for larger command usage updates.

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>

board/pcs440ep/pcs440ep.c

@@ -761,7 +761,7 @@ int do_led (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
 
 U_BOOT_CMD(
 	led,	2,	1,	do_led,
-	"led [bitmask]   - set the DIAG-LED\n",
+	"led	- set the DIAG-LED\n",
 	"[bitmask] 0x01 = DIAG 1 on\n"
 	"              0x02 = DIAG 2 on\n"
 	"              0x04 = DIAG 3 on\n"