Update sysfs paths to use /sys/class/fsi-master

The OpenBMC kernel as of 5.3 supports class based paths for the FSI
devices. This means each master (hardware master, or hub master) appears
under /sys/class/fsi-master, allowing a common path to be used no matter
the hub implementation.

Using this method allows us to the AST2600 hardware master and the
existing GPIO master in the same code base.

Signed-off-by: Joel Stanley <joel@jms.id.au>
Change-Id: Ie4ea1a66bf06c564b8212b10421b0a213b71f217
2 files changed