linux-phytec-ti

ARM: i.MX system: Simplify handling watchdog clock

This patch simplifies handling watchdog clock a bit.
As an additional change, now we properly check WDT clock in a reset
function.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Shawn Guo <shawn.guo@freescale.com>