Expose getSurfaceTransformHint API

The transform hint can be used by a buffer producer to pre-rotate
the rendering such that the final transformation in the system
composer is identity. This can be very useful when used in
conjunction with the h/w composer HAL in situations where it cannot
handle rotations or handle them with an additional power cost.

Bug: 196167822
Test: atest AttachedSurfaceControlTest
Change-Id: Idb7fcf58ecbcc22cd43c226ee4faad958c265e72