Pull in latest updates to AST driver.

* 'ast-updates' of ssh://people.freedesktop.org/~/linux:
  drm/ast: initial DP501 support (v0.2)
  drm/ast: rename the mindwm/moutdwm and deinline them
  drm/ast: resync the dram post code with upstream
  drm/ast: add AST 2400 support.
  drm/ast: add widescreen + rb modes from X.org driver (v2)