drm/gma500: Code cleanup - removal of centralized exiting of function

Removed centralized exiting of function (goto statement), since it was
the only used in one single location with only a return statement.

Signed-off-by: Arthur Borsboom <arthurborsboom@gmail.com>
Signed-off-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>