drm/amd/pm: Return -EOPNOTSUPP for unsupported OD_MCLK on smu_v13_0_6

drm/amd/pm: Return -EOPNOTSUPP for unsupported OD_MCLK on smu_v13_0_6

When SET_UCLK_MAX capability is absent, return -EOPNOTSUPP from
smu_v13_0_6_emit_clk_levels() for OD_MCLK instead of 0. This makes
unsupported OD_MCLK reporting consistent with other clock types
and allows callers to skip the entry cleanly.

Signed-off-by: Asad Kamal <asad.kamal@amd.com>
Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit d82e0a72d9189e8acd353988e1a57f85ce479e37)
Cc: stable@vger.kernel.org