drivers/fsi: Set up links for slave communication

Enable each link and send a break command, and try to detect a slave by
reading from the SMODE register.

Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>