v3d: support rendering to multi-layered framebuffers

v3d: support rendering to multi-layered framebuffers

When doing layered rendering the binning stage will prepare per-tile
lists for each layer in the framebuffer, so we need to make sure
we allocate enough space for them .

We also need to emit the NUMBER_OF_LAYERS packet. This is required
even when the number of layers is only 1, otherwise the simulator
detects buffer overflows in the tile_state BO during some CTS test
cases involving layered FBOs.

When rendering, we need to emit commands for each layer of the
framebuffer separately and make sure we address the correct layers for
each one.

v2: fixed typo in comment (Alejandro)

Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>