ABI: Update FSI path documentation

ABI: Update FSI path documentation

The paths added back in 4.13 weren't quite correct. The in reality the
files documented lived under

  /sys/devices/../fsi0/rescan
  /sys/devices/../fsi0/break
  /sys/devices/../fsi0/slave@00:00/term
  /sys/devices/../fsi0/slave@00:00/raw

In 5.5 with the addition of the FSI class they move to

  /sys/devices/../fsi-master/fsi0/rescan
  /sys/devices/../fsi-master/fsi0/break
  /sys/devices/../fsi-master/fsi0/slave@00:00/term
  /sys/devices/../fsi-master/fsi0/slave@00:00/raw

This is closer to how the (incorrect) documentation described them.

Signed-off-by: Joel Stanley <joel@jms.id.au>
Acked-by: Alistair Popple <alistair@popple.id.au>
Link: https://lore.kernel.org/r/20191108051945.7109-4-joel@jms.id.au
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>