msm: smd_debug: combine tbl and ch debugfs nodes into a single node

The tbl and ch debugfs node output different sets of SMD channel state
information.  The vast majority of issues require the output from both tbl
and ch for debug purposes.

For simplicity and to expedite debugging issues, replace the tbl and ch
nodes with a single node that combines the information.

Change-Id: I6afd1cd613412ea7efbdbfdeb799ba8a55dcaf67
Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org>