crypto: cleanup comments

For spdx
/* */ for *.h, // for *.c
Space before spdx tag

Replacements
paramenters to parameters
aymmetric to asymmetric
sigature to signature
boudary to boundary
compliled to compiled
eninges to engines
explicity to explicitly

Signed-off-by: Tom Rix <trix@redhat.com>
Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto/cfb.c

@@ -1,4 +1,4 @@
-//SPDX-License-Identifier: GPL-2.0
+// SPDX-License-Identifier: GPL-2.0
 /*
  * CFB: Cipher FeedBack mode
  *