msm: pcie: Change vendor name from 'qcom' to 'qti'

As we have recently moved to use 'qti' as the vendor name, reflect
that change for all PCIe related codes.

Change-Id: If0e937da65d111e504e3e7b2e57f949be9c30dff
Signed-off-by: Yan He <yanhe@codeaurora.org>