msm: camera: Changes to accommodate 32-bit Arch

This driver is using uint64_t to store pointers. On 64 bit uint64_t
and pointer is of the same size, but on the 32 bit system pointers are
smaller. Casting uint64_t to pointer generates warning on 32 bit
platforms.
Fix this by storing pointers as uintptr_t.

Change-Id: I7a8b7d5d7211000a975e79ff1eecf49d455a1dc6
Signed-off-by: Chandan Gera <cgera@codeaurora.org>