nvk: Implement VK_EXT_mutable_descriptor_type
CTS test results for dEQP-VK.binding_model.mutable_descriptor.*
:
Test run totals:
Passed: 3555/14304 (24.9%)
Failed: 0/14304 (0.0%)
Not supported: 10749/14304 (75.1%)
Warnings: 0/14304 (0.0%)
Waived: 0/14304 (0.0%)