cmd: ubi: Fix 'ubi list' command arguments parsing

This fixes allowed argc variable value for arguments parsing

Fixes: 6de1daf64b1 ("cmd: ubi: Add 'ubi list' command")
Signed-off-by: Dmitry Dunaev <dunaev@tecon.ru>
diff --git a/cmd/ubi.c b/cmd/ubi.c
index b61ae1e..0a6a80b 100644
--- a/cmd/ubi.c
+++ b/cmd/ubi.c
@@ -653,7 +653,7 @@
 
 	if (strcmp(argv[1], "list") == 0) {
 		int numeric = 0;
-		if (argc >= 2 && argv[2][0] == '-') {
+		if (argc >= 3 && argv[2][0] == '-') {
 			if (strcmp(argv[2], "-numeric") == 0)
 				numeric = 1;
 			else