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

Instead of exposing the arm-optimized SHA-1 code via arm-specific
crypto_shash algorithms, instead just implement the sha1_blocks()
library function.  This is much simpler, it makes the SHA-1 library
functions be arm-optimized, and it fixes the longstanding issue where
the arm-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.

To match sha1_blocks(), change the type of the nblocks parameter of the
assembly functions from int to size_t.  The assembly functions actually
already treated it as size_t.

Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20250712232329.818226-8-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>

arch/arm/configs/pxa_defconfig

@@ -658,7 +658,6 @@ CONFIG_CRYPTO_ANUBIS=m
 CONFIG_CRYPTO_XCBC=m
 CONFIG_CRYPTO_DEFLATE=y
 CONFIG_CRYPTO_LZO=y
-CONFIG_CRYPTO_SHA1_ARM=m
 CONFIG_CRYPTO_AES_ARM=m
 CONFIG_FONTS=y
 CONFIG_FONT_8x8=y