watchdog: s3c2410_wdt: Add support for WTCON register DBGACK_MASK bit

watchdog: s3c2410_wdt: Add support for WTCON register DBGACK_MASK bit

The WDT uses the CPU core signal DBGACK to determine whether the SoC
is running in debug mode or not. If the DBGACK signal is asserted and
DBGACK_MASK bit is enabled, then WDT output and interrupt is masked
(disabled).

Presence of the DBGACK_MASK bit is determined by adding a new
QUIRK_HAS_DBGACK_BIT quirk. Also update to use BIT macro to avoid
checkpatch --strict warnings.

Tested-by: Will McVicker <willmcvicker@google.com>
Reviewed-by: Sam Protsenko <semen.protsenko@linaro.org>
Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Link: https://lore.kernel.org/r/20231211162331.435900-11-peter.griffin@linaro.org
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>