Variable name 'LINUX' is very ambiguous for its purpose in the makefile.
Also, this project builds as a part of COHT project which uses another
variable name 'KERNELSRC' for the same purpose. Hence, this change makes
this project uniform with others.
Signed-off-by: Vaibhav Gupta <vaibhav.gupta@cern.ch>
Reviewed-by: Federico Vaga <federico.vaga@cern.ch>