drm/amd/display: Rename FAMS2 global control lock to DMUB HW control lock

drm/amd/display: Rename FAMS2 global control lock to DMUB HW control lock

[Why]
FAMS2 dictates whether the inbox0 HW lock is required, but it is not the
only feature that may determine this.

In order to leverage the faster inbox0 HW lock in place of the inbox1
ringbuffer based control lock it's desirable to utilize the HWSS
based locking protocol FAMS2 has already implemented.

[How]
Rename the FAMS2 global control lock to DMUB HW control lock.

This is purely a refactor with no functional change, the logic that will
determine which features need to enable this HW lock will be added in a
future commit.

Reviewed-by: Alvin Lee <alvin.lee2@amd.com>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Roman Li <roman.li@amd.com>
Tested-by: Dan Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>