FASTBOOT: Fix definition of "fastboot" command

The U_BOOT_CMD define for the "fastboot" command had a couple of
problems.  It allowed for a parameter which the code did nothing
with and the help would be formatted weird.

Change-Id: Ib4529bd895380069e7b616a7322df03d8ac5ce17
Signed-off-by: Scott Anderson <saa@google.com>
diff --git a/common/cmd_fastboot.c b/common/cmd_fastboot.c
index 415c388..fd99aae 100644
--- a/common/cmd_fastboot.c
+++ b/common/cmd_fastboot.c
@@ -1782,8 +1782,8 @@
 	return ret;
 }
 
-U_BOOT_CMD(fastboot, 2,	1, do_fastboot,
-	"fastboot- use USB Fastboot protocol", NULL);
+U_BOOT_CMD(fastboot, 1,	1, do_fastboot,
+	"use USB Fastboot protocol", NULL);
 
 /* Section for Android bootimage format support
  * Refer: