ANDROID: drm: kirin: Remove dead code that was causing build failures

Somehow in forward porting commit 34ebaf13 ("ANDROID: drm:
kirin: Introduce kirin960"), which moves a bunch of code around
to be shared, a chunk of code removal was dropped (likely due
to some minor collision).

This caused build failures w allmodconfig that I missed.

This patch removes the dead code causing the trouble.

Bug: 180655267
Fixes: 34ebaf13 ("ANDROID: drm: kirin: Introduce kirin960")
Reported-by: Todd Kjos <tkjos@google.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Change-Id: I79a727115756f213502de0a4406cf3384c393ead