It enables SAND modifier with columns 128-bytes-wide support for
NV12 format.

When a DRM_FORMAT_MOD_BROADCOM_SAND128 is enabled an imported NV12
texture format has a different layout. Luma and Chroma planes layout
is interleaved for every 128-bytes-wide columns.

Although TFU was supposed to convert a NV12 with SAND_COL128 modifier
from YUV to sRGB color space, it expects a particular swizzle that is not
the one provided by the video decoder available at the Raspberry Pi 4.

This patch follows a similar approach to VC4 YUV blit, using a custom
blit shader that transforms a NV12 texture with SAND_COL128 modifier
with the two interleaved planes to two not-interleaved textures with
UIF format, as it was a regular NV12 format texture.

To reduce the number of texture-fetch operations during the blit, we
are reading and writing the textures in pixel groups of 32-bits. This
implies some swizzling of the pixels to meet the particularities
of the different micro-tile layouts for 8bpp, 16bpp and 32bpp.

With this approach, we are not adding a new format that could be named
"NV12_SAND128". We are just enabling a format modifier.

v2: Rework checks for supported modifiers (Alejandro Piñeiro)
    Destroy custom shaders on context destroy (Alejandro Piñeiro)
    Add more comments (Alejandro Piñeiro)
    SAND128 in query_dmabuf_modifiers should report external_only true.

Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <!10051>