watchdog: da9063: Do not use a global variable

Using the 'use_sw_pm' variable as global is not recommended
as it prevents multi instances of the driver to run.

Make it a member of the da9063 structure instead.

Signed-off-by: Fabio Estevam <festevam@denx.de>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20241018135821.274376-1-festevam@gmail.com


Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>