dma-debug: debugfs_create_bool() takes a u32 pointer

Even though it has "bool" in the name, you have pass a u32 pointer to
debugfs_create_bool().  Otherwise you get memory corruption in
write_file_bool().  Fortunately in this case the corruption happens in
an alignment hole between variables so it doesn't cause any problems.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>