Build: Add central makefile to make build simpler for users

Signed-off-by: Frank Haverkamp <haver@linux.vnet.ibm.com>

Makefile

@@ -0,0 +1,26 @@
+#
+# Copyright 2018 International Business Machines
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+subdirs = afu_driver/src pslse libcxl debug
+
+all clean:
+	@for d in $(subdirs) ; do		\
+		$(MAKE) -C $$d $@  || exit 1;	\
+	done					\
+
+help:
+	@cat QUICK_START
+