staging: vc04_services: vc-sm-cma: Drop include Makefile directive

Drop the include directive. They can break the build, when one only
wants to build a subdirectory. Replace with "../" for the includes in
the vc_sm files instead.

The fix is equivalent to the four patches between 29d49a76
("staging: vc04_services: bcm2835-audio: Drop include Makefile
directive")...2529ca21 ("staging: vc04_services: interface: Drop
include Makefile directive")

Fixes: b1ab7a05 ("staging: vc04_services: Add new vc-sm-cma driver")
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>