watchdog: Intel SCU Watchdog Timer Driver for Moorestown and Medfield platforms.

This submission includes:
  - Fix to intel_scu_write() to start watchdog timer the on the
    first write, and refresh on subsequent writes.
    This enables Open, write, write, ... usage model.
  - Moves boot parameter checks from intel_scu_open() to
    intel_scu_watchdog_init(), so driver init will fail if these
    parameters are out of bounds.
  - Adds check for whether process waiting in wait_event_interruptible()
    received a signal while it was waiting.
  - Other small error handling changes.

Removed the read() method for now as that wass a non-standard behaviour.

Signed-off-by: Donald Johnson <donald.k.johnson@intel.com>
Signed-off-by: Shuduo Sang <shuduo.sang@intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>