crypto(9): Remove some unnecessary error handling.

[markj]

Summary

crypto_init() is called from a module load handler and is thus allowed
to sleep. So:

• uma_zcreate() doesn't fail, so stop handling failures
• stop handling M_WAITOK allocation failures
• convert M_NOWAIT allocations in crypto_init() to M_WAITOK
• fix some style bugs in crypto_init()

[delphij]

sys/opencrypto/crypto.c

328

[OPTIONAL] This should probably go in a different changeset, but I'm fine if it's left as-is too.

[jhb]

sys/opencrypto/cryptodev.c

1318

This one isn't crypto_init(), so I would perhaps commit it separately?

[markj]

sys/opencrypto/crypto.c

328

Since the whole thing is trivial cleanup, I tend to prefer just a single commit.

sys/opencrypto/cryptodev.c

1318

Ok. This bit actually comes from PR 240545.