Fix build issues when building on an ARM 64 platform

This patch arranges to have dpdk built with the
T=arm64-armv8a-linuxapp-gcc make option when building on
an ARM 64 platform.

Change-Id: I46d266af9171f02e78ed51cec8052c4f91304092
Signed-off-by: Barry Spinney <spinney@mellanox.com>
Reviewed-on: https://review.gerrithub.io/386708


Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Tested-by: SPDK Automated Test System <sys_sgsw@intel.com>