msm: mdss: support rotator sessions for high resolution surfaces

Each rotator block only supports up to 2048 width max, in order to
rotate bigger surfaces they need to be split and rotated in two separate
rotator blocks. Add support to manage this split internally and abstract
it to user.

Change-Id: Ib870bad5683aca7863e51043c2b7f487810e3eb1
Signed-off-by: Adrian Salido-Moreno <adrianm@codeaurora.org>