msm: mdss: disable bw release from rotator

For rotator path, display driver can release the rotator
bandwidth once the rotator finished processing. In some
scenarios this results in more power consumption since more
interrupts are generated to release the bandwidth.
This change disables the bandwidth release for the rotator path
and add a debugfs node to dynamically enable the feature if
needed.
To enable the bw release for rotator:
echo 1 > "<debugfs>/mdp/perf/enable_rotator_bw_release"
To disable the bw release for rotator (default):
echo 0 > "<debugfs>/mdp/perf/enable_rotator_bw_release"

Change-Id: If147b8fb202edcb389fe85e78f8d61d2a98cef95
Signed-off-by: Ingrid Gallardo <ingridg@codeaurora.org>