ARM: 7778/1: smp_twd: twd_update_frequency need be run on all online CPUs

When the local timer freq changed, the twd_update_frequency function
should be run all the CPUs include itself, otherwise, the twd freq will
not get updated and the local timer will not run correcttly.

smp_call_function will run functions on all other CPUs, but not include
himself, this is not correct,use on_each_cpu instead to fix this issue.

Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Shawn Guo <shawn.guo@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: stable@vger.kernel.org
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Jason Liu <r64343@freescale.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>