radv: Fix descriptors for cube images with VK_IMAGE_USAGE_STORAGE_BIT

radv: Fix descriptors for cube images with VK_IMAGE_USAGE_STORAGE_BIT

If a cube image has VK_IMAGE_USAGE_STORAGE_BIT set, the type in an image
view's descriptor was set to a 2D array (and a few other fields adjusted
accordingly). This is correct when the image view is actually bound as a
storage image, but not when bound as a sampled image. In that case the
type should be set as a cube.

Fix by generating 2 sets of descriptors at view creation time for both
storage and non-storage usage, and then choose between them based on
descriptor type when writing descriptor sets.

v2: Generate storage descriptors for images with TRANSFER_DST, since
    those may be used as storage images internally.

Signed-off-by: Alex Smith <asmith@feralinteractive.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>