Revert "msm: pcie: update PCIe PHY sequence on MSM8992"

This reverts commit 7826fbda.
This change adds the support to enable vbg optimization for
all targets on this branch. There is no support to enable
or disable the vbg optimization. Not all targets support
vbg optimization.

Change-Id: I1d01cf579009cb3ca204a2e2fdd36bd51474b338
Signed-off-by: Tony Truong <truong@codeaurora.org>