net: dsa: microchip: Fix uninitialized var in ksz9477_acl_move_entries()

Address an issue in ksz9477_acl_move_entries() where, in the scenario
(src_idx == dst_idx), ksz9477_validate_and_get_src_count() returns 0,
leading to usage of uninitialized src_count and dst_count variables,
which causes undesired behavior as it attempts to move ACL entries
around.

Fixes: 002841be ("net: dsa: microchip: Add partial ACL support for ksz9477 switches")
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Suggested-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://lore.kernel.org/r/20231006115822.144152-1-o.rempel@pengutronix.deSigned-off-by: Paolo Abeni <pabeni@redhat.com>

drivers/net/dsa/microchip/ksz9477_acl.c

@@ -420,10 +420,6 @@ static int ksz9477_validate_and_get_src_count(struct ksz_device *dev, int port,
 		return -EINVAL;
 	}
 
-	/* Nothing to do */
-	if (src_idx == dst_idx)
-		return 0;
-
 	/* Validate if the source entries are contiguous */
 	ret = ksz9477_acl_get_cont_entr(dev, port, src_idx);
 	if (ret < 0)
@@ -556,6 +552,10 @@ static int ksz9477_acl_move_entries(struct ksz_device *dev, int port,
 	struct ksz9477_acl_entries *acles = &acl->acles;
 	int src_count, ret, dst_count;
 
+	/* Nothing to do */
+	if (src_idx == dst_idx)
+		return 0;
+
 	ret = ksz9477_validate_and_get_src_count(dev, port, src_idx, dst_idx,
 						 &src_count, &dst_count);
 	if (ret)