phy: qcom-qmp-pcie: Split out EP related init sequence for SDX55

In preparation for adding RC support, let's split out the EP related init
sequence so that the common sequence could be reused by RC as well.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20230308082424.140224-12-manivannan.sadhasivam@linaro.org


Signed-off-by: Vinod Koul <vkoul@kernel.org>