msm: kgsl: Change name of vmalloc allocator

Change the vmalloc allocation name to something more appropriate since
we do not allocate memory using vmalloc for userspace driver. We
directly allocate physical pages and map that to user address space. The
name is changed to page_alloc instead of vmalloc. Add sysfs files to
track memory usage via both vmalloc and page_alloc.

Change-Id: I239087435f4599b62b7da71ecea0a5878cda5037
Signed-off-by: Harsh Vardhan Dwivedi <hdwivedi@codeaurora.org>