net: broadcom: bcm4908_enet: enable RX after processing packets

When receiving a lot of packets hardware may run out of free
descriptiors and stop RX ring. Enable it every time after handling
received packets.

Fixes: 4feffead

 ("net: broadcom: bcm4908enet: add BCM4908 controller driver")
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20210226132038.29849-1-zajec5@gmail.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>