net: add CRC implementation runtime selection

net: add CRC implementation runtime selection

This patch adds support for run-time selection of the optimal
architecture-specific CRC path, based on the supported instruction set(s)
of the CPU.

The compiler option checks have been moved from the C files to the meson
script. The rte_cpu_get_flag_enabled function is called automatically by
the library at process initialization time to determine which
instructions the CPU supports, with the most optimal supported CRC path
ultimately selected.

Signed-off-by: Mairtin o Loingsigh <mairtin.oloingsigh@intel.com>
Signed-off-by: David Coyle <david.coyle@intel.com>
Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
Reviewed-by: Jasvinder Singh <jasvinder.singh@intel.com>
Reviewed-by: Pablo de Lara <pablo.de.lara.guarch@intel.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>