radv: Disable VK_EXT_sample_locations on GFX10.

Workaround for mesa/mesa#2163

CC: <mesa-stable@lists.freedesktop.org>
Reviewed-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Tested-by: Marge Bot <mesa/mesa!3236>
Part-of: <mesa/mesa!3236>