Support Nuvoton pmw/tach fans

Support pwm/tach fans on the Nuvoton NPCM7xx BMC. They work similarly to
the already implemented Aspeed fans and can be detected by looking for
the device f0103000.pwm-fan-controller.

Tested: pwm and tach published to dbus when configured in
entity-manager json:

{
    "Name": "System fan connector 0",
    "Pwm": 0,
    "Status": "disabled",
    "Tachs": [0],
    "Type": "FanConnector"
},
{
    "Index": 0,
    "BindConnector": "System fan connector 0",
    "Name": "fan0",
    "Type": "NuvotonFan"
},

$ busctl --no-page tree xyz.openbmc_project.FanSensor
`-/xyz
  `-/xyz/openbmc_project
    |-/xyz/openbmc_project/control
    | `-/xyz/openbmc_project/control/fanpwm
    |   |-/xyz/openbmc_project/control/fanpwm/Pwm_1
    |   |-/xyz/openbmc_project/control/fanpwm/Pwm_2
    |   |-/xyz/openbmc_project/control/fanpwm/Pwm_3
    |   |-/xyz/openbmc_project/control/fanpwm/Pwm_4
    |   `-/xyz/openbmc_project/control/fanpwm/Pwm_5
    `-/xyz/openbmc_project/sensors
      |-/xyz/openbmc_project/sensors/fan_pwm
      | |-/xyz/openbmc_project/sensors/fan_pwm/Pwm_1
      | |-/xyz/openbmc_project/sensors/fan_pwm/Pwm_2
      | |-/xyz/openbmc_project/sensors/fan_pwm/Pwm_3
      | |-/xyz/openbmc_project/sensors/fan_pwm/Pwm_4
      | `-/xyz/openbmc_project/sensors/fan_pwm/Pwm_5
      `-/xyz/openbmc_project/sensors/fan_tach
        |-/xyz/openbmc_project/sensors/fan_tach/fan0
        |-/xyz/openbmc_project/sensors/fan_tach/fan1
        |-/xyz/openbmc_project/sensors/fan_tach/fan2
        |-/xyz/openbmc_project/sensors/fan_tach/fan3
        `-/xyz/openbmc_project/sensors/fan_tach/fan4

Signed-off-by: Peter Lundgren <peterlundgren@google.com>
Change-Id: Icf6cba1b8d4d33ccdd9b2dc9ba91209e4a5b2478