Regression: *ERROR* si_set_sw_state failed introduced by "drm/radeon/si_dpm: Replace one-element array with flexible-array in struct SISLANDS_SMC_SWSTATE"

Commit 96e27e8d919e52f30ea6b717e3cb70faa0b102cd ("drm/radeon/si_dpm: Replace one-element array with flexible-array in struct SISLANDS_SMC_SWSTATE") breaks SI dpm:

[    7.721796] [drm:si_dpm_set_power_state [radeon]] *ERROR* si_set_sw_state failed
[    7.793157] [drm:si_dpm_set_power_state [radeon]] *ERROR* si_restrict_performance_levels_before_switch failed
[    7.850516] [drm:si_dpm_set_power_state [radeon]] *ERROR* si_restrict_performance_levels_before_switch failed