drm/amd/pm: Fix output of pp_od_clk_voltage

Printing the other clock types should not be conditioned on being able
to print OD_SCLK. Some GPUs currently have limited capability of only
printing a subset of these.

Since this condition was introduced in v5.18-rc1, reading from
`pp_od_clk_voltage` has been returning empty on the Asus ROG Strix G15
(2021).

Fixes: 79c65f3f ("drm/amd/pm: do not expose power implementation details to amdgpu_pm.c")
Reviewed-by: Evan Quan <evan.quan@amd.com>
Signed-off-by: Jonatas Esteves <jntesteves@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org