amdgpu/pm: Fix incorrect variable for size of clocks array

 [v2]
No Changes, added RB
 [v1]
Size of pp_clock_levels_with_latency is PP_MAX_CLOCK_LEVELS, not MAX_NUM_CLOCKS.
Both are currently defined as 16, modifying in case one value is modified in future
Changed code in both arcturus and aldabaran.

Also removed unneeded var count, and used min_t function

Signed-off-by: Darren Powell <darren.powell@amd.com>
Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>