drm/vc4: Add firmware-kms mode

drm/vc4: Add firmware-kms mode

This is a squash of all firmware-kms related patches from previous
branches, up to and including
"drm/vc4: Set the possible crtcs mask correctly for planes with FKMS"
plus a couple of minor fixups for the 5.9 branch.
Please refer to earlier branches for full history.

This patch includes work by Eric Anholt, James Hughes, Phil Elwell,
Dave Stevenson, Dom Cobley, and Jonathon Bell.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
drm/vc4: Fixup firmware-kms after "drm/atomic: Pass the full state to CRTC atomic enable/disable"

Prototype for those calls changed, so amend fkms (which isn't
upstream) to match.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
drm/vc4: Fixup fkms for API change

Atomic flush and check changed API, so fix up the downstream-only
FKMS driver.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
drm/vc4: Make normalize_zpos conditional on using fkms

Eric's view was that there was no point in having zpos
support on vc4 as all the planes had the same functionality.

Can be later squashed into (and fixes):
drm/vc4: Add firmware-kms mode

Signed-off-by: Dom Cobley <popcornmix@gmail.com>
drm/vc4: FKMS: Change of Broadcast RGB mode needs a mode change

The Broadcast RGB (aka HDMI limited/full range) property is only
notified to the firmware on mode change, so this needs to be
signalled when set.

https://github.com/raspberrypi/firmware/issues/1580

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
vc4/drv: Only notify firmware of display done with kms

fkms driver still wants firmware display to be active

Signed-off-by: Dom Cobley <popcornmix@gmail.com>
ydrm/vc4: fkms: Fix margin calculations for the right/bottom edges

The calculations clipped the right/bottom edge of the clipped
range based on the left/top margins.

https://github.com/raspberrypi/linux/issues/4447

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
drm/vc4: fkms: Use new devm_rpi_firmware_get api

drm/kms: Add allow_fb_modifiers

Signed-off-by: Dom Cobley <popcornmix@gmail.com>