panfrost: Delay color buffer setup

panfrost: Delay color buffer setup

In an effort to cleanup framebuffer management code, we delay
colour buffer setup until the FRAGMENT job is actually emitted, allowing
the AFBC and linear codepaths to be unified.

Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Reviewed-by: Tomeu Vizoso <tomeu.visozo@collabora.com>