From: Tomáš Ďurovec <tomas.durovec@pantheon.tech>

Since the DPDK may already be built, some more general name
is needed that includes both the DPDK location and the build
config (if we are going to build).

Signed-off-by: Tomáš Ďurovec <tomas.durovec@pantheon.tech>
Signed-off-by: Luca Vizzarro <luca.vizzarro@arm.com>