drm/gma500: Make use of gma_pipe_has_type()

Replace any use of xxx_intel_pipe_has_type() with the generic
gma_pipe_has_type() function. Poulsbo still use it but that will be
removed when we rip out psb_intel_pipe_has_type().

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