platform/x86: mlx-platform: support new watchdog type with longer timeout

platform/x86: mlx-platform: support new watchdog type with longer timeout

Add verification of WD capability in order to distinguish between
the existing WD types and new type, implemented in CPLD.
Add configuration for a new WD type.
Change access mode for watchdog registers.

Signed-off-by: Michael Shych <michaelsh@mellanox.com>
Reviewed-by: Vadim Pasternak <vadimp@mellanox.com>
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20200504141427.17685-3-michaelsh@mellanox.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>