msm: camera: isp: Remove incorrect use of v4l2 type.

Isp driver uses V4L2 specific type in private ioctl. This is not
correct and also not necessary because isp kernel driver does not
actually need v4l2_buffer for this ioctl. This patch replaces the type
with ISP specific type, which satisfies its requirements.

Change-Id: Ic68f523617d14c1005d91a5e0a73ff1aff7345be
Signed-off-by: Petar Sivenov <psiven@codeaurora.org>