sf: Fix incorrect state reporting in dumpsys

Dumpsys utility access layer compositionType variable
with out proper protection. These variables are modified
during hwc_prepare call. Existing HAL lock protection is not
sufficient to address this issue. Failure to do this will
result in incorrect state reporting in dumpsys.

A new drawLock mutex in HWComposer that will be used in both
dumpsys and draw calls to ensure correct state is accessed.

Change-Id: I6289e0a3d1f5bbf35a18ddcd0538c9cda3e96c27