SF: Remove composer sequence IDs

Multiple HWC instances are no longer supported since VR was nixed.

Also, rename HAL callbacks so their origin is clear.

Bug: 182939859
Test: Build
Change-Id: Ia09b120dce1a4659a3cbb8927d44da8fba266c54
Merged-In: Ia09b120dce1a4659a3cbb8927d44da8fba266c54