Staging: bcm2835-audio: && vs & typo

We intended to mask away the upper bits but there is a "&&" vs "&" typo
so it's broken.

Fixes: 23b028c8

 ("staging: bcm2835-audio: initial staging submission")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>