msm: camera: isp: ispif: Get clock names and rates from dtsi files

Made changes in ISP, ISPIF driver to get clock names
and clock rates from corresponding camera dtsi files.
Earlier we had these values assigned in a structure
array. Cleaner way is to fetch values from dtsi files.

Change-Id: I737c2ed71cfbaea5f3af37a666a74f1fa177cc29
Signed-off-by: Krupal Divvela <kdivvela@codeaurora.org>