We should be careful to not call any functions besides fuzz_dma_read_cb.
Without --enable-fuzzing, fuzz_dma_read_cb is an empty inlined function.

Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Message-Id: <20201023150746.107063-7-alxndr@bu.edu>
Signed-off-by: Thomas Huth <thuth@redhat.com>