radv: enable VK_AMD_mixed_attachment_samples on GFX6-GFX7

Now that dEQP-VK.pipeline.multisample.mixed_attachment_samples.* pass,
it should be safe to also enable this extension on these old chips.

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4913>
diff --git a/docs/relnotes/new_features.txt b/docs/relnotes/new_features.txt
index 9cc3008..e442ced 100644
--- a/docs/relnotes/new_features.txt
+++ b/docs/relnotes/new_features.txt
@@ -13,3 +13,4 @@
 VK_KHR_shader_terminate_invocation on ANV
 driconf: add glx_extension_override
 driconf: add indirect_gl_extension_override
+VK_AMD_mixed_attachment_samples on RADV (GFX6-GFX7).
diff --git a/src/amd/vulkan/radv_extensions.py b/src/amd/vulkan/radv_extensions.py
index 5c68b13..e544cf2 100644
--- a/src/amd/vulkan/radv_extensions.py
+++ b/src/amd/vulkan/radv_extensions.py
@@ -173,8 +173,7 @@
     Extension('VK_AMD_gpu_shader_half_float',             2, 'device->rad_info.has_packed_math_16bit'),
     Extension('VK_AMD_gpu_shader_int16',                  2, 'device->rad_info.has_packed_math_16bit'),
     Extension('VK_AMD_memory_overallocation_behavior',    1, True),
-    # Disable mixed attachment samples on GFX6-GFX7 until the CTS failures have been resolved.
-    Extension('VK_AMD_mixed_attachment_samples',          1, 'device->rad_info.chip_class >= GFX8'),
+    Extension('VK_AMD_mixed_attachment_samples',          1, True),
     Extension('VK_AMD_rasterization_order',               1, 'device->rad_info.has_out_of_order_rast'),
     Extension('VK_AMD_shader_ballot',                     1, True),
     Extension('VK_AMD_shader_core_properties',            2, True),