comms/rxtx: fix build on powerpc by using correct jdk directory

Also remove not necessary NOT_FOR_ARCHS.

comms/rxtx/Makefile

@@ -13,9 +13,6 @@ WWW=		http://rxtx.qbang.org
 LICENSE=	LGPL21
 LICENSE_FILE=	${WRKSRC}/COPYING
 
-NOT_FOR_ARCHS=		mips mips64
-NOT_FOR_ARCHS_REASON=	Java not available for this architecture
-
 USES=		gmake java libtool zip
 
 JAVA_OS=	native
@@ -27,6 +24,6 @@ USE_LDCONFIG=	yes
 MAKE_JOBS_UNSAFE=	yes
 
 PLIST_SUB=	JAVA_HOME=${JAVA_HOME:S,^${PREFIX}/,,}
-PLIST_SUB+=	ARCH=${ARCH:C/armv.*/arm/:S/powerpc64/ppc64/}
+PLIST_SUB+=	ARCH=${ARCH:C/armv.*/arm/:S/powerpc/ppc/}
 
 .include <bsd.port.mk>