msm: kgsl: check for number of commands in kgsl_ioctl_gpu_aux_command

kgsl_ioctl_gpu_aux_command creates a separate drawobj for each command
in numcmds sent from userspace. All drawbojs created will have same
timestamp. We can not queue more than one drawobj with same timestamp.
Each new drawobj must have timestamp greater than previously queued
drawobjs. This results in failure of kgsl_ioctl_gpu_aux_command.
Add proper check and return early when numcmds is invalid.

Change-Id: I06413c16b0a21abcffb121b2e332752eb71e6be0
Signed-off-by: Pranav Patel <pranavp@codeaurora.org>
Signed-off-by: Akhil P Oommen <akhilpo@codeaurora.org>