drm/kmb: Add support for KeemBay Display

This is a basic KMS atomic modesetting display driver for KeemBay family of
SOCs. Driver has no 2D or 3D graphics. It calls into the ADV bridge
driver at the connector level.

Single CRTC with LCD controller->mipi DSI->ADV bridge

Only 1080p resolution and single plane is supported at this time.

v2: moved extern to .h, removed license text
    use drm_dev_init, upclassed dev_private, removed HAVE_IRQ.(Sam)

v3: Squashed all 59 commits to one

v4: review changes from Sam Ravnborg
	renamed dev_p to kmb
	moved clocks under kmb_clock, consolidated clk initializations
	use drmm functions
	use DRM_GEM_CMA_DRIVER_OPS_VMAP

v5: corrected spellings
v6: corrected checkpatch warnings
v7: review changes Sam Ravnborg and Thomas Zimmerman
	removed kmb_crtc.h kmb_crtc_cleanup (Thomas)
	renamed mode_set, kmb_load, inlined unload (Thomas)
	moved remaining logging to drm_*(Thomas)
	re-orged driver initialization (Thomas)
	moved plane_status to drm_private (Sam)
	removed unnecessary logs and defines and ifdef codes (Sam)
	call helper_check in plane_atomic_check (Sam)
	renamed set to get for bpp and format functions(Sam)
	use drm helper functions for reset, duplicate/destroy state instead
	of kmb functions (Sam)
	removed kmb_priv from kmb_plane and removed kmb_plane_state (Sam)
v8: get clk_pll0 from display node in dt
v9: moved csc_coef_lcd to plane.c (Daniel Vetter)
    call drm_atomic_helper_shutdown in remove (Daniel V)
    use drm_crtc_handle_vblank (Daniel V)
    renamed kmb_dsi_hw_init to kmb_dsi_mode_set (Daniel V)
    complimentary changes to device tree changes (Rob)
v10: call drm_crtc_arm_vblank_event in atomic_flush (Daniel V)
     moved global vars to kmb_private and added locks (Daniel V)
     changes in driver to accommodate changes in DT to separate DSI
     entries (Sam R)
     review changes to separate mipi DSI (Sam R)
v11: review changes to separate msscam (Neil A,Sam R)
v12: fixed warnings Reported-by: kernel test robot <lkp@intel.com>

Signed-off-by: Anitha Chrisanthus <anitha.chrisanthus@intel.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/1604538931-26726-6-git-send-email-anitha.chrisanthus@intel.com