watchdog: iTCO_wdt: Cleanup warning messages

The current iTCO_wdt driver warnings are confusing.  Currently when the device
driver returns an error the console contains:

iTCO_vendor_support: vendor-support=0
iTCO_wdt: Intel TCO WatchDog Timer Driver v1.05
iTCO_wdt: failed to reset NO_REBOOT flag, reboot disabled by hardware
iTCO_wdt: No card detected

After the patch,

iTCO_vendor_support: vendor-support=0
iTCO_wdt: Intel TCO WatchDog Timer Driver v1.05
iTCO_wdt: failed to reset NO_REBOOT flag, device disabled by hardware/BIOS

Clean this up and use the word "device" to describe the device.

Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>