r8169: enable napi on resume.

NAPI is disabled during suspend and needs to be enabled on resume. Without
this the driver locks up during resume in rtl_reset_work() trying to disable
NAPI again.

Signed-off-by: Artem Savkov <artem.savkov@gmail.com>
Acked-by: Francois Romieu <romieu@fr.zoreil.com>
Signed-off-by: David S. Miller <davem@davemloft.net>