staging: ti dspbridge: use node id instead of kernel address

Use idr kernel library to send/receive node ids to the
user instead of kernel address.
This id will be use to access the node handles at the
kernel side, if id does not match to any handle
error -EFAULT is returned.

Signed-off-by: Ernesto Ramos <ernesto@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>