Mako: Set for JWR kernel

Change-Id: I721d5a829db48c33cb613a2cd3a6c3412a1420f2
mako: do not use global cpp flag

at least the result is the same but let us user the
propper way like we do it with all flags and do not
set if over a global cpp flag

Change-Id: I1b7a229226af96cdfd294752823939a2cf870649

Conflicts:
	BoardConfig.mk