ARM: dts: msm: Add DT node for VBUS detect on sdxpoorwills

Add the DT node for pmd-vbus-det driver which supports
VBUS detection over SPMI interrupts.

Enable this the PCIe EP device tree file for CDP and MTP.

Change-Id: Iad5369e197354318f8e3588d9e94cb72344dfb48
Signed-off-by: Anirudh Ghayal <aghayal@codeaurora.org>