This syncs up the mode code from the X.org driver upstream,
and adds the mode validation step for hw that doesn't have
widescreen.

v2: (from Egbert Eich <eich@suse.de)
squash drm/ast: Use correct structure member for mode validation
to avoid bisect regression.

In struct drm_display_mode crtc_hdisplay and crtc_vdisplay are holding
the crtc parameters after mode fixup. For validation we need hdisplay and
vdisplay.
Signed-off-by: NEgbert Eich <eich@suse.de>
Signed-off-by: NDave Airlie <airlied@redhat.com>

This is the initial driver for the Aspeed Technologies chips found in
servers. This driver supports the AST 2000, 2100, 2200, 2150 and 2300. It
doesn't support the AST11xx due to lack of hw to test it on, and them requiring
different codepaths.

This driver is intended to be used with xf86-video-modesetting in userspace.

This driver has a slightly different design than other KMS drivers, but
future server chips will probably share similiar setup. As these GPUs commonly
have low video RAM, it doesn't make sense to put the kms console in VRAM
always. This driver places the kms console into system RAM, and does dirty
updates to a copy in video RAM. When userspace sets a new scanout buffer,
it forcefully evicts the video RAM console, and X can create a framebuffer
that can use all of of video RAM.

This driver uses TTM but in a very simple fashion to control the eviction
to system RAM of the console, and multiple servers.

v2: add s/r support, fix Kconfig.
Signed-off-by: NDave Airlie <airlied@redhat.com>