Revert "drm/amd: Disable S/G for APUs when 64GB or more host memory"

Revert "drm/amd: Disable S/G for APUs when 64GB or more host memory"

This reverts commit 70e64c4d522b732e31c6475a3be2349de337d321.

Since, we now have an actual fix for this issue, we can get rid of this
workaround as it can cause pin failures if enough VRAM isn't carved out
by the BIOS.

Cc: stable@vger.kernel.org # 6.1+
Acked-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>