net: ethernet: aquantia: Fixed memory allocation if AQ_CFG_RX_FRAME_MAX > 1 page.

We should allocate the number of pages based on the config parameter
AQ_CFG_RX_FRAME_MAX.

Signed-off-by: Pavel Belous <pavel.belous@aquantia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>