staging: most: cdev: rename class instance aim_class

This patch renames the instance  aim_class of struct class to comp_class.
It is needed to complete the process of changing the module designator from
AIM to Component.

Signed-off-by: Christian Gromm <christian.gromm@microchip.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>