[ARM SMP] mpcore_wdt bogus fpos check

drivers/char/watchdog/mpcore_wdt.c write function contains a check for
(ppos != &file->f_pos). Such check used to make sense when a pointer to
file->f_pos was handed by vfs_write(), not a copy of it as it stands
now.

Signed-off-by: Marcelo Tosatti <marcelo.tosatti@cyclades.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>