drm/msm/sde: add debugfs support for misr data

This change adds a debugfs node to enable the misr
crc generation in batch mode. Once this is enabled,
driver will collect the crc numbers during each of
the interfaces interrupt.

To enable/disable the crc generation, respectively:

echo 1 16 > /d/dri0/encoder18/misr_data
echo 0 16 > /d/dri0/encoder18/misr_data

Inputs here represents enable and number of frame in batch.
Maximum batch size supported is 16.

To collect the crc data generated:

cat /d/dri0/encoder18/misr_data

Change-Id: I0a431b1ceff0425bec10d8739ad07a7b706b5f57
Signed-off-by: Jayant Shekhar <jshekhar@codeaurora.org>