hostmot2: sserial: add notes about interpreting fault bits
hostmot2: sserial: add notes about interpreting fault bits

.. adapted from IRC conversations with PCW

Signed-off-by: Jeff Epler <623a871f32baaca066adfe0cac08d7aa7d34027d@unpythonic.net>

ikcalB/linuxcnc-mirror,ikcalB/linuxcnc-mirror,ikcalB/linuxcnc-mirror,ikcalB/linuxcnc-mirror,ikcalB/linuxcnc-mirror,ikcalB/linuxcnc-mirror,ikcalB/linuxcnc-mirror