Documentation: add RDNA4 dGPUs

Add RDNA4 dGPUs to the dGPU table.

Link: https://www.amd.com/en/products/graphics/desktops/radeon/9000-series/amd-radeon-rx-9070xt.html
Link: https://www.amd.com/en/products/graphics/desktops/radeon/9000-series/amd-radeon-rx-9070.html
Link: https://www.amd.com/en/products/graphics/desktops/radeon/9000-series/amd-radeon-rx-9060xt.html
Link: https://www.amd.com/en/products/graphics/desktops/radeon/9000-series/amd-radeon-rx-9060xt-8gb.html


Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>