SFH sensors are not working on some AMD platforms

[Alex Hung]

[Impact]

When amd-sfh is loaded the sensors connected do not change values at all (ALS sensor).

  Here is the monitor sensors output, which doesn't change.

  $ sudo monitor-sensor
    Waiting for iio-sensor-proxy to appear
  +++ iio-sensor-proxy appeared
  === No accelerometer
  === Has ambient light sensor (value: 0.000000, unit: lux)

[Fix]

  The SRU contains two fixes:
  1. increasing sensor command timeout from from 800000 to 1600000.
  2. using first valid 15 bits only ALS max illuminance values.

[Test]

  This is requested by AMD. This was also verified by an AMD's engineer on CRB.

[Where problems could occur]

  Low. The patches only increase timeout value and discard an invalid bit.