build: force pkg-config for dependency detection

build: force pkg-config for dependency detection

Meson can use cmake as a fallback for detecting packages, and this can
lead to picking up 64-libs for 32-bit builds. To work around this, force
the use of pkg-config only for detecting libcrypto, zlib, jansson and
other package dependencies.

Cc: stable@dpdk.org
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Tested-by: Ruifeng Wang <ruifeng.wang@arm.com>
Tested-by: Liron Himi <lironh@marvell.com>
Tested-by: Lee Daly <lee.daly@intel.com>
Tested-by: Hemant Agrawal <hemant.agrawal@nxp.com>
Tested-by: Martin Spinler <spinler@cesnet.cz>