watchdog: s3c2410_wdt: add wdt_stop_intclear function

watchdog: s3c2410_wdt: add wdt_stop_intclear function

In 4.9 kernel porting,
I excluded the 8289222f1db85a6b0af0387e21ceb2f6e5d5a5d4 patch.
There is already a related patch, 882dec1ff125e9020157d27672ec11c2fdfb82c2.
In this Patch, I removed all functions and variables associated with the 8289222f1.. patch.

Sometimes watchdog interrupt is pended in booting time before
initialize watchdog timer. In this case system can be reboot
from thi interrupt.

This patch clear watchdog interrupt before watchdog reset enable
to ignore interrupt in booting time. And code is move after
wdt clock initialize.

Change-Id: I2900ae733f9b24c8c4a84ef030be29cb06f19727
Signed-off-by: Hyunki Koo <hyunki00.koo@samsung.com>
Signed-off-by: Hosung Kim <hosung0.kim@samsung.com>
Signed-off-by: Changki Kim <changki.kim@samsung.com>
Signed-off-by: Choi Jaehyoung <jkkkkk.choi@samsung.com>