board-msm7x30: Increase the camera heap for framebuffer allocation
On jb_mr1, framebuffer surfaces also need to be allocated from
user-space. We can not fall back system heap for framebuffer
allocations. MDP couldn't access buffers from system heap.

So, the memory requirement for physically contigiuous buffers has
gone up. Increase the size of camera_preview heap (ADSP) by
3 * (required memory for 32 bpp framebuffer).

This increase is needed, as we have use-cases like stress tests,
which will put more load onto pmem_adsp.

CRs-Fixed: 457812

Change-Id: I6689aecfb4002e8ed32e55c4dad5de37fb94c13d
Signed-off-by: Neti Ravi Kumar <ravineti@codeaurora.org>