clk: clock-local2: Correct enabling the XO_DIV4 clock

The current sequence used to enable the CXO/4 measurement
reference clock is incorrect. Read the register value and
flip the zero bit in order for measurement to work.

Change-Id: I7219565e1f7d90f74bc4498d8e1cfd574b50de9c
Signed-off-by: Deepak Katragadda <dkatraga@codeaurora.org>