zink: Fix VK_FORMAT_A8B8G8R8_SRGB_PACK32 mapping on big-endian
The PACK32 Vulkan formats need to map to the corresponding XYZWxxxx pipe formats, since the latter take endianness into account. Reviewed-by:Eric Anholt <eric@anholt.net> Reviewed-by:
Erik Faye-Lund <erik.faye-lund@collabora.com> Part-of: <mesa/mesa!8394>