wined3d: Use VK_FORMAT_R4G4B4A4_UNORM_PACK16 for WINED3DFMT_B4G4R4A4_UNORM.
We can query support for this format without checking for an extension.
VK_EXT_4444_formats introduces VK_FORMAT_A4R4G4B4_UNORM_PACK16_EXT,
which is a native fit, but we have to introduce extension checks to
vulkan_formats[].