drm/radeon: bind fan control on CI cards to hwmon interface (v2)

This adds a possibility to control fan on CI parts
via exported hwmon variables. Note that automatic
ucode fan management pauses if you choose to enable
manual fan control.  Use with caution!

v2: agd5f: fix formatting, squash in:

    minor fix for pwm1_enable exposed value

    Track smc control in addition to fan mode
    This fixes pwm1_enable being constantly set
    to 1 because of enabled smc control

also handle the case where smc fan control is disabled.

Signed-off-by: Oleg Chernovskiy <algonkvel@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>