msm: pcie: add PCIe bus driver snapshot

This change ports PCIe bus driver and its dependecies from
msm-4.4 to msm-4.9. All the files are as is from msm-4.4.
Changes to pci-msm.c were made to adhere to current coding
standards.

This PCIe bus driver snapshot is taken as of msm-4.4
commit 283e8d1b9311
("mmc: sdhci-msm: Disable controller clocks in suspend").

Change-Id: Ia1a2d0eea0cc87c16357c95bfcc4df72e910cd34
Signed-off-by: Tony Truong <truong@codeaurora.org>