dri: Add fp16 formats

Add dri formats for RGBA ordered 64 bpp IEEE 754 half precision floating
point. Leverage existing offscreen render support for
MESA_FORMAT_RGBA_FLOAT16 and MESA_FORMAT_RGBX_FLOAT16.

Signed-off-by: Kevin Strasser <kevin.strasser@intel.com>
Reviewed-by: Adam Jackson <ajax@redhat.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
4 files changed