msm: camera: Get max vfe clk rate

Add support to query max vfe clk rate. This max rate shall be used
by mm-qcamera-daemon user space driver to populate its capabilities
and to assign vfe resources based on request.

Change-Id: Ib65b73424d725e2d3e50e2ce2030d2f1b09e7514
Signed-off-by: Sreesudhan Ramakrish Ramkumar <srramku@codeaurora.org>