panfrost: Mark buffers as PANFROST_BO_HEAP

panfrost: Mark buffers as PANFROST_BO_HEAP

What we call GROWABLE in Mesa corresponds to the HEAP BO flag in the
kernel. These buffers cannot be memory mapped in the CPU side at the
moment, so make sure they are also marked INVISIBLE.

This allows us to allocate a big heap upfront (16MB) without actually
reserving space unless it's needed.

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