net: ethernet: adi: adin1110: Fix multicast offloading

Driver marked broadcast/multicast frames as offloaded incorrectly.
Mark them as offloaded only when HW offloading has been enabled.
This should happen only for ADIN2111 when both ports are bridged
by the software.

Fixes: bc93e19d

 ("net: ethernet: adi: Add ADIN1110 support")
Signed-off-by: Alexandru Tachici <alexandru.tachici@analog.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20230120090846.18172-1-alexandru.tachici@analog.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>