drm/amdgpu/gfx11: Add missing break

This stops clang complaining:

drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c:5895:2: warning: unannotated fall-through between switch labels [-Wimplicit-fallthrough]
        default:
        ^
drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c:5895:2: note: insert 'break;' to avoid fall-through
        default:
        ^
        break;
Signed-off-by: Mike Lothian <mike@fireburn.co.uk>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c

@@ -5886,6 +5886,7 @@ static int gfx_v11_0_set_priv_inst_fault_state(struct amdgpu_device *adev,
 		WREG32_FIELD15_PREREG(GC, 0, CP_INT_CNTL_RING0,
 			       PRIV_INSTR_INT_ENABLE,
 			       state == AMDGPU_IRQ_STATE_ENABLE ? 1 : 0);
+		break;
 	default:
 		break;
 	}