Fix a wrong memory access in hpet_ioctl_common().  It was not possible to use
the HPET_INFO ioctl from kernel space because it always called copy_to_user().

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Cc: Bob Picco <bob.picco@hp.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>