i965/surface_formats: add support for 2D ASTC surface formats

i965/surface_formats: add support for 2D ASTC surface formats

Define two-thirds of the 2D Intel ASTC surface formats (LDR-only). This allows
a 1-to-1 mapping from the mesa format to the Intel format.

ASTC textures will default to being processed in LDR mode. If there is
hardware support for HDR/Full mode and the texture is not sRGB, add the
format bit necessary to process it in HDR/Full mode.

v2: remove extra newlines.
v3: follow existing coding style in translate_tex_format().
v4: expound on the GEN9_SURFACE_ASTC_HDR_FORMAT_BIT comment.
    update SF table - ASTC is actually supported in Gen8.
v5: conform the ASTC MESA_FORMAT enums to the existing naming convention.

Reviewed-by: Anuj Phogat <anuj.phogat@gmail.com>
Signed-off-by: Nanley Chery <nanley.g.chery@intel.com>