msm: ep_pcie: add PCIe endpoint driver snapshot

Snapshot of PCIe endpoint driver as of msm-4.9.

'commit <16158207fb4c> ("Merge "f_qc_rndis: Call
rndis_ipa_init() from rndis_qc_bind()")'.

Update handling of error conditions.

Change-Id: I55070402c9acb0edfb5ffe162cdb70a839cfabb3
Signed-off-by: Rama Krishna Phani A <rphani@codeaurora.org>