msm: camera: Implement reg cmd list update for ISP

Iterate through the list in ioctl handler and perform multilple
hardware update in single ioctl call. This support is required
for minimizing ioctl calls from multiple ISP modules. hw update
list is created in user space from individual modules and provided
to kernel in single ioctl call.

Change-Id: I991d1819bc69a6d78cc6226525e9cd593677df70
Signed-off-by: Sreesudhan Ramakrish Ramkumar <srramku@codeaurora.org>