staging: bcm2835-audio: deallocate work when queue_work(...) fails

This patch de-allocates work when queue_work(..) fails in the
bcm2835-audio work functions

Signed-off-by: Aishwarya Pant <aishpant@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>