[WATCHDOG] it8712f_wdt support for 16-bit timeout values, WDIOC_GETSTATUS

This patch adds support for 16-bit watchdog timeout values which are
available in chip revisions >= 0x08. Values <= 65535 are seconds precision,
otherwise minutes precision is used up to a maximum value of 3932100. Added
implementation for WDIOC_GETSTATUS which checks the WDT status bit in the
WDT control register.

Signed-off-by: Andrew Paprocki <andrew@ishiboo.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>