drm/format-helper: Add RGB565-to-XRGB8888 conversion

commit 81d9529eccbb362490a8b64c91cb3c5429bdb9d4 from
https://nv-tegra.nvidia.com/r/3rdparty/canonical/linux-jammy.git

 jetson_36.3

Add a format helper that converts RGB565 to XRGB8888. Use this
function in drm_fb_blit_toio(). Fixes simpledrm output for this
combination of formats.

UEFI and/or Grub will usually set 32-bit output in XRGB8888 format.
The issue can be reproduced by enabling simpledrm and requesting a
console framebuffer of different format on the kernel command line;
for example

  nomodeset video=1024x768-16

In this case, conversion helpers will display nothing on the console.
The patch makes this work by implementing the rsp conversion helpers.
It also enables odd userspace configurations, such as running Xorg
with 16-bit color depth on a 32-bit output buffer.

v2:
	* use helpers for struct drm_rect (Javier)
	* improve commit message (Javier)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220425075939.30450-4-tzimmermann@suse.de


(cherry picked from commit e08a99d0)
Change-Id: I0910904008a2e92bf95b0a5e63aba303b94bdce2
Signed-off-by: Thierry Reding <treding@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/c/3rdparty/canonical/linux-jammy/+/2985842


Reviewed-by: svcacv <svcacv@nvidia.com>
Reviewed-by: Jonathan Hunter <jonathanh@nvidia.com>
GVS: Gerrit_Virtual_Submit <buildbot_gerritrpt@nvidia.com>
Signed-off-by: Rajeshkumar Ramasamy <rajeshkumar.ramasamy@windriver.com>