drivers: watchdog: wdt_dw: add watchdog disable at boot and pause by debug

added support for watchdog enable/disable at boot

Pausing watchdog timer when CPU is halted by the debugger and
pausing watchdog timer when CPU is in sleep state is not
configurable through application, so added warning log with return success

Signed-off-by: Balsundar Ponnusamy <balsundar.ponnusamy@intel.com>