msm: kgsl: Fix kvcalloc() calls

Depending on user input the size of the page struct that we try to
allocate with kvcalloc() could be way too big. Add __GFP_NOWARN and
__GFP_NORETRY to keep from invoking the OOM killer in these cases.

Also remove an unneeded usage of kvmalloc() since the maximum allocation
size for the HFI command will only be 1k as enforced on the previous
line.

Change-Id: Ic0dedbad8d09544bdc0070b9b797616ee1f672d4
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>