misc lib/raid/ improvements

[Christoph Hellwig]

Hi all,

this series improves the benchmark-based algorithm selection and
adds kunit benchmarks for both the XOR and raid6 libraries, and tidies
up a few very minor other bits.

diffstat:
 lib/raid/Kconfig                   |   15 ++++++
 lib/raid/raid6/Makefile            |    2 
 lib/raid/raid6/algos.c             |  112 +++++++++++++++++++++++++---------------------
 lib/raid/raid6/tests/raid6_kunit.c |   66 ++++++++++++++++++++++++++-
 lib/raid/xor/Makefile              |    2 
 lib/raid/xor/tests/Makefile        |    2 
 lib/raid/xor/tests/xor_kunit.c     |   64 +++++++++++++++++++++++++-
 lib/raid/xor/xor-core.c            |   55 ++++++++++------------
 8 files changed, 236 insertions(+), 82 deletions(-)