greybus: properly cleanup ida and idr structures when shutting down

idr and ida structures have internal memory allocated that needs to be
freed when modules are removed.  So call the proper idr_destroy() or
ida_destroy() functions on the module exit path to free the memory.

Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Reviewed-by: Alex Elder <elder@linaro.org>