drm: Move the legacy kms disable_all helper to crtc helpers

drm: Move the legacy kms disable_all helper to crtc helpers

It's not a core function, and the matching atomic functions are also
not in the core. Plus the suspend/resume helper is also already there.

Needs a tiny bit of open-coding, but less midlayer beats that I think.

v2: Rebase onto ast (which gained a new user).

Cc: Sam Bobroff <[email protected]>
Reviewed-by: Alex Deucher <[email protected]>
Reviewed-by: Sean Paul <[email protected]>
Signed-off-by: Daniel Vetter <[email protected]>
Cc: Maarten Lankhorst <[email protected]>
Cc: Maxime Ripard <[email protected]>
Cc: Sean Paul <[email protected]>
Cc: David Airlie <[email protected]>
Cc: Ben Skeggs <[email protected]>
Cc: Alex Deucher <[email protected]>
Cc: "Christian König" <[email protected]>
Cc: "David (ChunMing) Zhou" <[email protected]>
Cc: Rex Zhu <[email protected]>
Cc: Andrey Grodzovsky <[email protected]>
Cc: Huang Rui <[email protected]>
Cc: Shaoyun Liu <[email protected]>
Cc: Monk Liu <[email protected]>
Cc: [email protected]
Cc: [email protected]
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]