drm/amdgpu: Enable chained IB MCBP support

Support for MCBP/Virtualization in combination with chained IBs is
formal released on firmware feature version #46. So enable it
according to firmware feature version, otherwise, world switch will
hang.

Signed-off-by: Trigger Huang <trigger.huang@amd.com>
Reviewed-by: Monk Liu <monk.liu@amd.com>
Reviewed-by: Xiangliang Yu <Xiangliang.Yu@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>