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

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: 002841be134e ("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.de
Signed-off-by: Paolo Abeni <pabeni@redhat.com>