msm: kgsl: add egl_surface/egl_image usage count in debugfs

Add more information to the debugfs kgsl/proc/<pid>/mem which
will allow memtrack to correctly assign allocated ion buffer
memory to a process. The additional columns show the number of
kgsl_mem_entries which have a usage of egl_image (or) egl_surface.

When attaching a dma_buf to kgsl, use the dma_buf_attachment's
(void*)priv to point back to the kgsl_mem_entry. This makes it
possible to iterate through all attachments on a dma_buf and
gather statistics from each kgsl_mem_entry associated with the
dma_buf.

CRs-Fixed: 1073673
Change-Id: I1ef3bd0da3f74fa41074021699b2226c48bde9c3
Signed-off-by: Santhosh Punugu <spunug@codeaurora.org>