nvk: Advertise EXT_4444_formats

nvk: Advertise EXT_4444_formats

The following tests now pass:

dEQP-VK.texture.filtering.2d.formats.a4b4g4r4_unorm.nearest
dEQP-VK.texture.filtering.2d.formats.a4b4g4r4_unorm.linear
dEQP-VK.texture.filtering.2d.formats.a4b4g4r4_unorm.nearest_mipmap_nearest
dEQP-VK.texture.filtering.2d.formats.a4b4g4r4_unorm.linear_mipmap_nearest
dEQP-VK.texture.filtering.2d.formats.a4b4g4r4_unorm.nearest_mipmap_linear
dEQP-VK.texture.filtering.2d.formats.a4b4g4r4_unorm.linear_mipmap_linear

The corresponding tests for a4r4g4b4_unorm are still passing.

Closes: https://gitlab.freedesktop.org/nouveau/mesa/-/issues/36

Signed-off-by: Rebecca Mckeever <rebecca.mckeever@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/24326>