drm/ast: Load lut in crtc_commit

drm/ast: Load lut in crtc_commit

In the past the ast driver relied upon the fbdev emulation helpers to
call ->load_lut at boot-up. But since

commit b8e2b0199cc377617dc238f5106352c06dcd3fa2
Author: Peter Rosin <[email protected]>
Date:   Tue Jul 4 12:36:57 2017 +0200

    drm/fb-helper: factor out pseudo-palette

that's cleaned up and drivers are expected to boot into a consistent
lut state. This patch fixes that.

Fixes: b8e2b0199cc3 ("drm/fb-helper: factor out pseudo-palette")
Cc: Peter Rosin <[email protected]>
Cc: Daniel Vetter <[email protected]>
Cc: <[email protected]> # v4.14+
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=198123
Cc: Bill Fraser <[email protected]>
Reported-and-Tested-by: Bill Fraser <[email protected]>
Signed-off-by: Daniel Vetter <[email protected]>
Signed-off-by: Dave Airlie <[email protected]>