Use crc32 wrapper (VPP-1086)

Use crc32 wrapper (VPP-1086)

This allows arm platforms to also take advantage of crc32 hardware
acceleration.

* add a wrapper for crc32_u64. It's the only one really used. Using it
  instead of a call to clib_crc32c() eases building symmetrical hash
  functions.
* replace #ifdef on SSE4 by a test on clib_crc32c_uses_intrinsics.
  Note: keep the test on i386
* fix typo in lb test log

Change-Id: I03a0897b70f6c1717e6901d93cf0fe024d5facb5
Signed-off-by: Gabriel Ganne <[email protected]>