lib/crypto: s390/sha1: Migrate optimized code into library

lib/crypto: s390/sha1: Migrate optimized code into library

Instead of exposing the s390-optimized SHA-1 code via s390-specific
crypto_shash algorithms, instead just implement the sha1_blocks()
library function.  This is much simpler, it makes the SHA-1 library
functions be s390-optimized, and it fixes the longstanding issue where
the s390-optimized SHA-1 code was disabled by default.  SHA-1 still
remains available through crypto_shash, but individual architectures no
longer need to handle it.

Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20250712232329.818226-12-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>