msm: kgsl: Replace 325Mhz with 320 Mhz for 8064 and 8960PRO

325Mhz will not be supported anymore and has to be replaced
with 320Mhz.

Change-Id: Ibdb678215749d0e57b66e6e6416c5cb978b45b66
Signed-off-by: Suman Tatiraju <sumant@codeaurora.org>
Signed-off-by: Neha Pandey <nehap@codeaurora.org>