panfrost: Move sysval upload logic out of panfrost_emit_for_draw()

panfrost: Move sysval upload logic out of panfrost_emit_for_draw()

We're about to add more sysval types, and panfrost_emit_for_draw()
is big enough, so let's move the sysval upload logic in a separate
function.

We also add one sub-function per sysval type to keep the
panfrost_upload_sysvals() small/readable.

Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>