i2c: fsi: Add of_put_node() before break

Each iteration of for_each_available_childe_of_node puts the previous
node, but in the case of a break from the middle of the loop, there
is no put, thus causing a memory leak. Add an of_node_put before the
break.
Issue found with Coccinelle.

Signed-off-by: Nishka Dasgupta <nishkadg.linux@gmail.com>
Reviewed-by: Eddie James <eajames@linux.ibm.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>