drm/amd/pp: Add OVERDRIVE support on Vega10 (v2)

when bit14 in module parameter ppfeaturemask was set.
od feature will be enabled on Vega10 except vbios not support.

user can read od range by reading sysfs pp_od_clk_voltage,
cat pp_od_clk_voltage
OD_SCLK:
0:        852Mhz        800mV
1:        991Mhz        900mV
2:       1138Mhz        950mV
3:       1269Mhz       1000mV
4:       1348Mhz       1050mV
5:       1399Mhz       1100mV
6:       1440Mhz       1150mV
7:       1500Mhz       1200mV
OD_MCLK:
0:        167Mhz        800mV
1:        500Mhz        800mV
2:        800Mhz        950mV
3:        945Mhz       1000mV
OD_RANGE:
SCLK:     852MHz       2200MHz
MCLK:     167MHz       1500MHz
VDDC:     800mV        1200mV

and can configure the clock/voltage by writing pp_od_clk_voltage
for example:

echo "s 0 900 820">pp_od_clk_voltage to change the sclk/vddc
to 900MHz and 820 mV in dpm level0.

echo "r" to change the clk/voltage to  default value.

echo "c">pp_od_clk_voltage
to commit the change

v2: squash in warning fix (Alex)

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Rex Zhu <Rex.Zhu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>