msm: kgsl: Add CMA memory feature to support NOMMU for GPU

Reserves CMA memory for kgsl driver early during bootup and then
uses dma_alloc_coherent() to allocate physically contiguous memory
instead of using the MMU

Change-Id: Ica9b244fe9b9d8a902d670293a0bec2edf81bd5d
Signed-off-by: Shrenuj Bansal <shrenujb@codeaurora.org>