msm: ep_pcie: init the MMIO before link training

Host side could access MMIO as soon as the PCIe link is up. Config
all MMIO registers which are related to the init of host side,
before the PCIe link training.

Change-Id: I0e6dd19b7945d2518d3af79f4ed6290f36c0d7e0
Signed-off-by: Yan He <yanhe@codeaurora.org>