powerpc/fsl_soc: Remove mpc83xx_wdt_init, again

commit b31a1d8b ("gianfar: Convert
gianfar to an of_platform_driver"), possibly due merge issues,
reintroduced completely unneded mpc83xx_wdt_init call, which
I removed some time ago in commit 20d38e01
("powerpc/fsl_soc: remove mpc83xx_wdt code").

Remove it once again.

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>