uniflash.inc.mk: add `CCS_PATH` variable.
uniflash.inc.mk: add `CCS_PATH` variable.

This is used now to set the `DEBUGSSERVER` as the `gdb_agent_console`
file was removed from UniFlash.

Signed-off-by: Jean Pierre Dudey <341388fa1817ca285e65547384a9727ce7f6d39a@hotmail.com>

smlng/RIOT,kaspar030/RIOT,kaspar030/RIOT,kYc0o/RIOT,OTAkeys/RIOT,jasonatran/RIOT,miri64/RIOT,miri64/RIOT,toonst/RIOT,kaspar030/RIOT,smlng/RIOT,yogo1212/RIOT,ant9000/RIOT,smlng/RIOT,RIOT-OS/RIOT,ant9000/RIOT,kaspar030/RIOT,basilfx/RIOT,ant9000/RIOT,OlegHahm/RIOT,RIOT-OS/RIOT,authmillenon/RIOT,kaspar030/RIOT,yogo1212/RIOT,toonst/RIOT,OlegHahm/RIOT,yogo1212/RIOT,authmillenon/RIOT,OTAkeys/RIOT,x3ro/RIOT,kYc0o/RIOT,yogo1212/RIOT,toonst/RIOT,smlng/RIOT,x3ro/RIOT,OTAkeys/RIOT,x3ro/RIOT,kYc0o/RIOT,kYc0o/RIOT,RIOT-OS/RIOT,miri64/RIOT,miri64/RIOT,toonst/RIOT,authmillenon/RIOT,basilfx/RIOT,jasonatran/RIOT,jasonatran/RIOT,OlegHahm/RIOT,toonst/RIOT,ant9000/RIOT,authmillenon/RIOT,miri64/RIOT,RIOT-OS/RIOT,jasonatran/RIOT,OTAkeys/RIOT,kYc0o/RIOT,OlegHahm/RIOT,yogo1212/RIOT,x3ro/RIOT,OTAkeys/RIOT,basilfx/RIOT,ant9000/RIOT,x3ro/RIOT,basilfx/RIOT,authmillenon/RIOT,yogo1212/RIOT,OlegHahm/RIOT,smlng/RIOT,RIOT-OS/RIOT,jasonatran/RIOT,authmillenon/RIOT,basilfx/RIOT