msm: Adjust the low memory boundary

The unused virtual address space in low memory is given to
vmalloc for use. This reduces the low memory space and
increases vmalloc space. Adjust the vmalloc_min in order
to increase the low memory.

Change-Id: I0dbef5b6e5ec3d19f5f93f06ed03a4cf1215dc4d
Signed-off-by: Neeti Desai <neetid@codeaurora.org>