Fix test-dts{,o} targets

There were two main problems here:

1.) sys/dts/Makefile.inc is not included from various */overlays directories
    by default, only ../Makefile.inc
2.) When shelling out for DTS/DTSO, cwd != .CURDIR, so enumeration always
    failed

These changes allow make test-dts and make test-dtso to function in their
respective directories.

Reviewed by:	manu
MFC after:	3 days
Differential Revision:	https://reviews.freebsd.org/D17961

sys/dts/Makefile.inc

@@ -5,9 +5,9 @@ SYSDIR?=${SRCTOP}/sys
 test-dts:
 .for dts in ${DTS}
 	@env MACHINE=`basename ${.CURDIR}` ${SYSDIR}/tools/fdt/make_dtb.sh ${SYSDIR} ${dts} /tmp
+.endfor
 
 test-dtso:
 .for dtso in ${DTSO}
 	@env MACHINE=`basename ${.CURDIR}` ${SYSDIR}/tools/fdt/make_dtbo.sh ${SYSDIR} ${dtso} /tmp
-
 .endfor

sys/dts/arm/Makefile

@@ -1,6 +1,6 @@
 # $FreeBSD$
 
-DTS!=ls *.dts
+DTS!=ls ${.CURDIR}/*.dts
 
 all: test-dts
 

sys/dts/arm/Makefile.inc

@@ -0,0 +1,3 @@
+# $FreeBSD$
+
+.include "../Makefile.inc"

sys/dts/arm/overlays/Makefile

@@ -1,6 +1,6 @@
 # $FreeBSD$
 
-DTSO!=ls *.dtso
+DTSO!=ls ${.CURDIR}/*.dtso
 
 all: test-dtso
 

sys/dts/arm64/Makefile

@@ -1,6 +1,6 @@
 # $FreeBSD$
 
-DTS!=ls *.dts
+DTS!=ls ${.CURDIR}/*.dts
 
 all: test-dts
 

sys/dts/arm64/Makefile.inc

@@ -0,0 +1,3 @@
+# $FreeBSD$
+
+.include "../Makefile.inc"

sys/dts/arm64/overlays/Makefile

@@ -1,6 +1,6 @@
 # $FreeBSD$
 
-DTSO!=ls *.dtso
+DTSO!=ls ${.CURDIR}/*.dtso
 
 all: test-dtso
 

sys/dts/mips/Makefile

@@ -1,6 +1,6 @@
 # $FreeBSD$
 
-DTS!=ls *.dts
+DTS!=ls ${.CURDIR}/*.dts
 
 all: test-dts
 

sys/dts/powerpc/Makefile

@@ -1,6 +1,6 @@
 # $FreeBSD$
 
-DTS!=ls *.dts
+DTS!=ls ${.CURDIR}/*.dts
 
 all: test-dts