net: check max SIMD bitwidth

net: check max SIMD bitwidth

When choosing a vector path to take, an extra condition must be
satisfied to ensure the max SIMD bitwidth allows for the CPU enabled
path.

The vector path was initially chosen in RTE_INIT, however this is no
longer suitable as we cannot check the max SIMD bitwidth at that time.
Default handlers are now chosen on initialisation, these default
handlers are used the first time the crc calc is called, and they set
the suitable handlers to be used going forward.

Suggested-by: Jasvinder Singh <jasvinder.singh@intel.com>
Suggested-by: Olivier Matz <olivier.matz@6wind.com>
Signed-off-by: Ciara Power <ciara.power@intel.com>
Acked-by: Jasvinder Singh <jasvinder.singh@intel.com>