pci: msm: Refactor endpoint event registration

For endpoint event registration do not depend on
num_ep, active_num_ep and pending_ep_reg variables.
Instead, create a list of registered endpoints and
notify an endpoint by iterating over the list of
registered endpoints with their corresponding
registered event. This also removes dependency on
PCIe device table and simplifies
msm_pcie_config_device_table function. Keep the
handling of upstream port I/O, memory and BME.

Change-Id: I5ab25ef300f0bc59ae5c2d973c662a0f81e44f43
Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>