msm: camera2: cpp: Fix iommu_attach/detach compat_ioctl issue

When the Camera application exercises 32-bit version of the V4L2 ioctl
operation, it results accessing  user space  memory illegally. This is
due to the direct access of user space buffer by Camera CPP driver.

Thus, fix this by copying user space buffer contents into kernel space
buffer of the  driver for  further processing. Only after checking for
proper length of user space buffer, proceed further. This will prevent
the buffer overflow and invalid memory access.

CRs-fixed: 2025367
Change-Id: I85cf4a961884c7bb0d036299b886044aef7baf7c
Signed-off-by: Ravi kumar Koyyana <rkoyyana@codeaurora.org>