Move cc2538dk travis tests to the arm-aapcs job

It makes sense to test cc2538dk with the toolchain recommended in the README (GNU Tools for ARM Embedded Processors) rather than the one which was being used two years ago (Sourcery G++ Lite)

.travis.yml

@@ -30,7 +30,7 @@ before_script:
   - sudo apt-get -qq install libc6:i386 libgcc1:i386 gcc-4.6-base:i386
       libstdc++5:i386 libstdc++6:i386
 
-  ## Install old APCS ARM toolchain for mc1233x, cc2538 and mbxxx
+  ## Install old APCS ARM toolchain for mc1233x and mbxxx
   - if [ ${BUILD_ARCH:-0} = arm-apcs ] ; then
       $WGET https://raw.githubusercontent.com/wiki/malvira/libmc1322x/files/arm-2008q3-66-arm-none-eabi-i686-pc-linux-gnu.tar.bz2 &&
       tar xjf arm-2008q3*.tar.bz2 -C /tmp/ &&

regression-tests/15-compile-arm-apcs-ports/Makefile

@@ -4,19 +4,10 @@ TOOLSDIR=../../tools
 EXAMPLES = \
 hello-world/econotag \
 hello-world/mbxxx \
-hello-world/cc2538dk \
 ipv6/rpl-border-router/econotag \
-ipv6/rpl-border-router/cc2538dk \
 er-rest-example/econotag \
-er-rest-example/cc2538dk \
 webserver-ipv6/econotag \
-webserver-ipv6/cc2538dk \
-cc2538dk/cc2538dk \
-cc2538dk/udp-ipv6-echo-server/cc2538dk \
-cc2538dk/sniffer/cc2538dk \
-cc2538dk/mqtt-demo/cc2538dk \
 ipv6/multicast/econotag \
-ipv6/multicast/cc2538dk \
 
 TOOLS=
 

regression-tests/18-compile-arm-ports/Makefile

@@ -8,6 +8,15 @@ webserver-ipv6/ev-aducrf101mkxz \
 ipv6/multicast/ev-aducrf101mkxz \
 cc2538dk/sniffer/ev-aducrf101mkxz \
 cc26xx/cc26xx-web-demo/srf06-cc26xx \
+hello-world/cc2538dk \
+ipv6/rpl-border-router/cc2538dk \
+er-rest-example/cc2538dk \
+webserver-ipv6/cc2538dk \
+cc2538dk/cc2538dk \
+cc2538dk/udp-ipv6-echo-server/cc2538dk \
+cc2538dk/sniffer/cc2538dk \
+cc2538dk/mqtt-demo/cc2538dk \
+ipv6/multicast/cc2538dk \
 
 TOOLS=