ARM: dts: msm: add PCIe AUX clk freq for controller for sdxlemur

Replace deprecated PCIe DT entry for PCIe AUX clock controller
setting with the correct entry and value. PCIe core controller
requires AUX clock to be 16.6MHz for sdxlemur.

Change-Id: I2fa8d8c819bfd06f80b2e274f97b282caa90eb70