minigbm: virtgpu: add resource create blob function

minigbm: virtgpu: add resource create blob function

Some SW intensive apps could benefit from this.

This should decrease power consumption when playing a Youtube
1080p60fps video by 10%.

BUG=chromium:924405
TEST=mmap_test

Change-Id: I80bb08a95b7387eb8af58e1f0d30beb695fc3e74
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/minigbm/+/1804914
Tested-by: Gurchetan Singh <gurchetansingh@chromium.org>
Reviewed-by: Lingfeng Yang <lfy@google.com>
Reviewed-by: Jason Macnak <natsu@google.com>
Reviewed-by: Gurchetan Singh <gurchetansingh@chromium.org>
Commit-Queue: Gurchetan Singh <gurchetansingh@chromium.org>