crypto: x86/aegis128 - improve assembly function prototypes

Adjust the prototypes of the AEGIS assembly functions:

- Use proper types instead of 'void *', when applicable.

- Move the length parameter to after the buffers it describes rather
  than before, to match the usual convention.  Also shorten its name to
  just len (which is the name used in the assembly code).

- Declare register aliases at the beginning of each function rather than
  once per file.  This was necessary because len was moved, but also it
  allows adding some aliases where raw registers were used before.

- Put assoclen and cryptlen in the correct order when declaring the
  finalization function in the .c file.

- Remove the unnecessary "crypto_" prefix.

Reviewed-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>