mvebu: a38x: Force receiver detected on PCIe lanes

mvebu: a38x: Force receiver detected on PCIe lanes

Some QCA988x based modules presence is not detected by the SERDES lanes,
so force this detection which will trigger the LTSSM state machine to
negotiate link.

An example of such a card is WLE900VX.

Signed-off-by: Rabeeh Khoury <rabeeh@solid-run.com>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Tested-by: Chris Packham <judge.packham@gmail.com>
Tested-by: Mario Six <mario.six@gdsys.cc>
Signed-off-by: Stefan Roese <sr@denx.de>