rtw88: remove a copy of the NAPI_POLL_WEIGHT define

Defining local versions of NAPI_POLL_WEIGHT with the same
values in the drivers just makes refactoring harder.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20220429174643.196994-2-kuba@kernel.org