intel: Add PIPE_FORMAT_R10G10B10X2_UNORM support

This utilizes the RGBX format faking logic from e8cd7a30 to enable
PIPE_FORMAT_R10G10B10X2_UNORM renderer support using swizzling.

This format is needed for better HDR rendering support in the iris driver, to
support the Proton / Wine DXGI implementation, which requires an RGBA ordered
renderer for its Vulkan implementation. This in turn requires the Wayland
display to support both alpha and opaque formats. The check currently fails,
since only PIPE_FORMAT_R10G10B10A2_UNORM is exposed when Gallium (iris) is
the DRI Wayland renderer.

Cc: mesa-stable
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/38616>
(cherry picked from commit 858364be71)

.pick_status.json

@@ -24,7 +24,7 @@
         "description": "intel: Add PIPE_FORMAT_R10G10B10X2_UNORM support",
         "nominated": true,
         "nomination_type": 1,
-        "resolution": 0,
+        "resolution": 1,
         "main_sha": null,
         "because_sha": null,
         "notes": null

src/intel/isl/isl_format.c

@@ -688,6 +688,7 @@ isl_format_for_pipe_format(enum pipe_format pf)
       [PIPE_FORMAT_R16G16B16X16_SINT]       = ISL_FORMAT_R16G16B16A16_SINT,
       [PIPE_FORMAT_R32G32B32X32_UINT]       = ISL_FORMAT_R32G32B32A32_UINT,
       [PIPE_FORMAT_R32G32B32X32_SINT]       = ISL_FORMAT_R32G32B32A32_SINT,
+      [PIPE_FORMAT_R10G10B10X2_UNORM]       = ISL_FORMAT_R10G10B10A2_UNORM,
       [PIPE_FORMAT_R10G10B10X2_SNORM]       = ISL_FORMAT_R10G10B10A2_SNORM,
    };
    assert(pf < PIPE_FORMAT_COUNT);