fix(plat/marvell/armada): select correct pcie reference clock source

when comphy is in pcie mode, correct reference clock need be
selected according to SAR register that reflect the CPx_MPP boot
strapping pins. Either from external or from internal

Signed-off-by: Guo Yi <yguo@cavium.com>
Reviewed-by: Kostya Porotchkin <kostap@marvell.com>
Change-Id: I99ed64a141e85174cc0f8e9dab5886ab2506efa1
1 file changed