driver-core: fix DEVICE_INT_ATTR to use correct show/store functions

DEVICE_INT_ATTR() should use device_show_int() and device_store_int()
not device_show_ulong() and device_store_ulong()

Signed-off-by: Michael Davidson <md@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>