libgui: Remove unnecessary casts in SurfaceControl

There are a number of places where we create a local
sp<SurfaceComposerClient>& to something that is already an
sp<SurfaceComposerClient>, which is redundant. This fixes that
by removing the local references.

Bug: 13814149
Change-Id: Ic558cbda651c344e5cac97022c97563928eed29c
1 file changed