staging: bcm2835-camera: fix module autoloading

In order to make the module bcm2835-camera load automatically, we need to
add a module alias.

Fixes: 4bebb031 ("staging/bcm2835-camera: Set ourselves up as a platform driver.")
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>