Staging: batman-adv: consistent spelling of "neighbors"

we have written "neighbors", "neighbours" and bad spelled versions of this
word, this patch should make it consistent.

Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>