drm/amd/pm: Fix showing incorrect frequencies on aldebaran

v1: Use the current and custom pstate frequencies to track the current and
user-set min/max values in manual and determinism mode. Previously, only
actual_* value was used to track the currrent and user requested value.
The value will get reassigned whenever user requests a new value with
pp_od_clk_voltage node. Hence it will show incorrect values when user
requests an invalid value or tries a partial request without committing
the values. Separating out to custom and current variable fixes such
issues.

v2: Remove redundant if-else check

Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Kevin Wang <kevin1.wang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>