The checksum benchmarking on module load may take a really long time
on embedded systems with a slow cpu. Avoid all benchmarks >= 1MiB on
systems, where EdonR is slower then 300 MiB/s.
This limit is currently hardcoded via the define LIMIT_PERF_MBS.
This is the new benchmark output of a slow Intel Atom:
```
implementation 1k 4k 16k 64k 256k 1m 4m 16m
edonr-generic 209 257 268 259 262 0 0 0
skein-generic 129 150 151 150 150 0 0 0
sha256-generic 50 55 56 56 56 0 0 0
sha512-generic 76 86 88 89 88 0 0 0
blake3-generic 63 62 62 62 61 0 0 0
blake3-sse2 114 292 301 307 309 0 0 0
```
Reviewed-by: Sebastian Gottschall <s.gottschall@dd-wrt.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tino Reichardt <milky-zfs@mcmilk.de>
Closes#13695
68aa3379ec