staging: bcm2835-audio: replace printk(KERN_ERR...) with dev_err(...)

Use dev_err(... in place of printk(KERN_ERR ...
Problem found by checkpatch

Signed-off-by: Aishwarya Pant <aishpant@gmail.com>
Acked-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>