cmd: hash: correct parameter count check

Since commit 348ea878508d ("cmd: hash: fix param count check") the hash
command cannot be used without the optional variable name parameter if
CONFIG_HASH_VERIFY=y. 'hash sha1 $loadaddr $filesize' returns
CMD_RET_USAGE.

The minimum number of arguments is four no matter if verification is
enabled or not.

Fixes: 348ea878508d ("cmd: hash: fix param count check")
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Igor Opaniuk <igor.opaniuk@gmail.com>
diff --git a/cmd/hash.c b/cmd/hash.c
index 60d482b..5b40982 100644
--- a/cmd/hash.c
+++ b/cmd/hash.c
@@ -25,7 +25,7 @@
 	char *s;
 	int flags = HASH_FLAG_ENV;
 
-	if (argc < (HARGS - 1))
+	if (argc < 4)
 		return CMD_RET_USAGE;
 
 #if IS_ENABLED(CONFIG_HASH_VERIFY)