LINUX: move afs_notify_change to osi_vnodeops.c

LINUX: move afs_notify_change to osi_vnodeops.c

afs_notify_change is almost always used solely in inode_operations
structs, and is more similar to the other per-vnode functions. Put it
with the other per-vnode functions for better organization, and so
they can use the same static functions.

Move the helper functions iattr2vattr and vattr2inode along with it.

Change-Id: I47a69fe673cfc3318ce583596ba25cbeb9cb0b96
Reviewed-on: http://gerrit.openafs.org/6775
Reviewed-by: Derrick Brashear <shadow@dementix.org>
Tested-by: BuildBot <buildbot@rampaginggeek.com>