msm: Increase the kernel virtual area to include lowmem

Even though lowmem is accounted for in vmalloc space,
allocation comes only from the region bounded by
VMALLOC_START and VMALLOC_END. The kernel virtual area
can now allocate from any unmapped region starting
from PAGE_OFFSET.

Change-Id: I291b9eb443d3f7445fd979bd7b09e9241ff22ba3
Signed-off-by: Neeti Desai <neetid@codeaurora.org>
Signed-off-by: Susheel Khiani <skhiani@codeaurora.org>