staging: bcm2835-audio: Fixed spacing around '&'

This was reported by checkpatch.pl

Signed-off-by: Narcisa Ana Maria Vasile <narcisaanamaria12@gmail.com>
Acked-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>