lib/crypto: arm64/polyval: Migrate optimized code into library

lib/crypto: arm64/polyval: Migrate optimized code into library

Migrate the arm64 implementation of POLYVAL into lib/crypto/, wiring it
up to the POLYVAL library interface.  This makes the POLYVAL library be
properly optimized on arm64.

This drops the arm64 optimizations of polyval in the crypto_shash API.
That's fine, since polyval will be removed from crypto_shash entirely
since it is unneeded there.  But even if it comes back, the crypto_shash
API could just be implemented on top of the library API, as usual.

Adjust the names and prototypes of the assembly functions to align more
closely with the rest of the library code.

Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20251109234726.638437-5-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>