vulkan/format: Use correct swizzle for 1-plane YCbCr formats

vulkan/format: Use correct swizzle for 1-plane YCbCr formats

VK_FORMAT_G8B8G8R8_422_UNORM and VK_FORMAT_B8G8R8G8_422_UNORM already
place the luminance channel in the green component which is where we NIR
lowering code for ycbcr expects it.  Set an RGBA swizzle in the common
format table and make it the driver's responsibility to re-map the
formats as needed for their hardware.

The only Vulkan drivers affected by this change are the Intel drivers
and lavapipe.  None of NVK, RADV, and v3dv support these formats yet and
Turnip has its own lowering that doesn't rely on the YCbCr format table
in util/vk_format.c.

Reviewed-by: Dave Airlie <airlied@redhat.com>
Reviewed-by: Roland Scheidegger <sroland@vmware.com>
Acked-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/24619>