drm/amdkfd: fix partition query when setting up recommended sdma engines

When users dynamically set the partition mode through sysfs writes,
this can lead to a double lock situation where the KFD is trying to take
the partition lock when updating the recommended SDMA engines.
Have the KFD reference its saved socket device number count instead.
Also ensure we have enough SDMA xGMI engines to report the recommended
engines in the first place.

Fixes: e06b71b2 ("drm/amdkfd: allow users to target recommended SDMA engines")
Signed-off-by: Jonathan Kim <jonathan.kim@amd.com>
Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>