watchdog: s3c2410: Implement a way to invert mask reg value

watchdog: s3c2410: Implement a way to invert mask reg value

On new Exynos chips (like Exynos850) the MASK_WDT_RESET_REQUEST register
is replaced with CLUSTERx_NONCPU_INT_EN, and its mask bit value meaning
was reversed: for new register the bit value "1" means "Interrupt
enabled", while for MASK_WDT_RESET_REQUEST register "1" means "Mask the
interrupt" (i.e. "Interrupt disabled").

Introduce "mask_reset_inv" boolean field in driver data structure; when
that field is "true", mask register handling function will invert the
value before setting it to the register.

This commit doesn't bring any functional change to existing devices, but
merely provides an infrastructure for upcoming chips support.

Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20211107202943.8859-8-semen.protsenko@linaro.org
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>