Fixed local declaration of IOSurfaceRef.

IOSrufaceRef is declared as "typedef struct __IOSurface *" in latest OS
X SDK in IOSurface.framework/IOSurfaceAPI.h, line 17.

Regal's declaration of IOSurfaceRef as a void * results in a compile
error on OS X / Xcode when both Regal and IOSurface headers are
included.