Revert "drm/amdgpu: work around lack of upstream ACPI support for D3cold"

This reverts commit c63695cc5e5f685e924e25a8f9555f6e846f1fc6.

Now that d3cold support is upstream, there is no more need for this
workaround.

bug:
https://bugs.freedesktop.org/show_bug.cgi?id=97248

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

@@ -200,16 +200,7 @@ static int amdgpu_atpx_validate(struct amdgpu_atpx *atpx)
 	atpx->is_hybrid = false;
 	if (valid_bits & ATPX_MS_HYBRID_GFX_SUPPORTED) {
 		printk("ATPX Hybrid Graphics\n");
-#if 1
-		/* This is a temporary hack until the D3 cold support
-		 * makes it upstream.  The ATPX power_control method seems
-		 * to still work on even if the system should be using
-		 * the new standardized hybrid D3 cold ACPI interface.
-		 */
-		atpx->functions.power_cntl = true;
-#else
 		atpx->functions.power_cntl = false;
-#endif
 		atpx->is_hybrid = true;
 	}