drm/amd/powerplay: fix byte alignment issue of smu11 pptable

The smu_11_0_powerplay_table, smu_11_0_power_saving_clock_table, and
smu_11_0_overdrive_table need byte alignment. So we must add packed attribute
in the definitions.

Signed-off-by: Huang Rui <ray.huang@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Kenneth Feng <kenneth.feng@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>