Move pkg-config override to beginning in the Makefile to allow
use PKGCONF variable to detect the libdpdk availability.
Fixes: fda34680eb ("examples: remove legacy sections of makefiles")
Cc: stable@dpdk.org
Signed-off-by: Jerin Jacob <jerinj@marvell.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>