Add iputils-ping to the build scripts

iputils-ping is a required tool for yocto-2.3.

Change-Id: I51834fbc542f88c5f1e673428edb9a56a4f58862
Signed-off-by: Saqib Khan <khansa@us.ibm.com>
diff --git a/kernel-build-setup.sh b/kernel-build-setup.sh
index 89c2d2f..84eb6f5 100755
--- a/kernel-build-setup.sh
+++ b/kernel-build-setup.sh
@@ -37,6 +37,7 @@
 	gcc-arm-linux-gnu \
 	hostname \
 	make \
+	iputils-ping \
 	uboot-tools xz
 
 RUN grep -q ${GROUPS} /etc/group || groupadd -g ${GROUPS} ${USER}