drm/amd/pm: improve the fine grain tuning function for RV/RV2/PCO

This patch is to improve the fine grain tuning function for RV/RV2/PCO.
The fine grain tuning function uses the sysfs node -- pp_od_clk_voltage
to config gfxclk. Meanwhile, another sysfs
node -- power_dpm_force_perfomance_level also affects the gfx clk.
It will cause confusion when these two sysfs nodes works
together. So this patch adds one flag to avoid this confusion, the flag
will make these two sysfs nodes work separately.
The flag is set as "disabled" by default, so the fine grain tuning function
will be disabled by default.
Only when power_dpm_force_perfomance_level is changed to
"manual" mode, the flag will be set as "enabled",
and the fine grain tuning function will be enabled.
In other profile modes, including "auto", "high", "low",
"profile_peak", "profile_standard", "profile_min_sclk",
"profile_min_mclk", the flag will be set as "disabled",
and the od range of fine grain tuning function will
be restored default value.

Signed-off-by: Xiaojian Du <Xiaojian.Du@amd.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>