msm: pcie: remove aggregation of PCIe rate change clock vote

Chipsets on msm-5.4 does not require PCIe bus driver to
aggregate each PCIe port rate change clock vote. Therefore,
remove the support for it.

Change-Id: I670f045b36c7473d5fc285a1cb45a8175b755dcb
Signed-off-by: Tony Truong <truong@codeaurora.org>