wlcore/wl12xx: move rx_mem_pool_addr element to wl12xx

Only wl127x chips use the rx_mem_pool_addr values, which need to be
given to the firmware as part of the RX path.  Move this from core to
the wl12xx driver.

Signed-off-by: Luciano Coelho <coelho@ti.com>
Signed-off-by: Arik Nemtsov <arik@wizery.com>