[WATCHDOG] wdt285: fix sparse warnings

The wdt285.c watchdog driver is producing a number of
sparse errors due to missing __user attributes to calls
to put_user and copy_to_user, as well as in the prototype
of watchdog_write.

wdt285.c:144:21: warning: incorrect type in argument 1 (different address spaces)
wdt285.c:144:21:    expected void [noderef] <asn:1>*to
wdt285.c:144:21:    got void *<noident>
wdt285.c:150:9: warning: incorrect type in initializer (different address spaces)
wdt285.c:150:9:    expected int const [noderef] <asn:1>*register __p
wdt285.c:150:9:    got int *<noident>
wdt285.c:159:9: warning: incorrect type in initializer (different address spaces)
wdt285.c:159:9:    expected int const [noderef] <asn:1>*register __p
wdt285.c:159:9:    got int *<noident>
wdt285.c:174:9: warning: incorrect type in initializer (different address spaces)
wdt285.c:174:9:    expected int const [noderef] <asn:1>*register __p
wdt285.c:174:9:    got int *<noident>
wdt285.c:183:12: warning: incorrect type in initializer (incompatible argument 2 (different address spaces))
wdt285.c:183:12:    expected int ( *write )( ... )
wdt285.c:183:12:    got int ( static [toplevel] *<noident> )( ... )

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>