[WATCHDOG] sbc_fitpc2_wdt: fix I/O space access technique.

The mdelay function was used between I/O access commands, that causes peak
in CPU usage. Fix it by substitution mdelay to msleep.

Expand usage on fitPC2 compatible boards according to DMI identification.

Signed-off-by: Denis Turischev <denis@compulab.co.il>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>