panfrost: Select format-specific blending intrinsics

If we have an accelerated path for a particular framebuffer format,
let's use it to save a bunch of instructions in a blend shader.

[Tomeu: Only use the faster intrinsic on >T760]

Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Reviewed-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
3 files changed