crypto: nhpoly1305 - add NHPoly1305 support

Add a generic implementation of NHPoly1305, an ε-almost-∆-universal hash
function used in the Adiantum encryption mode.

CONFIG_NHPOLY1305 is not selectable by itself since there won't be any
real reason to enable it without also enabling Adiantum support.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/crypto/Makefile b/crypto/Makefile
index 102e852..c3310c8 100644
--- a/crypto/Makefile
+++ b/crypto/Makefile
@@ -85,6 +85,7 @@
 obj-$(CONFIG_CRYPTO_XTS) += xts.o
 obj-$(CONFIG_CRYPTO_CTR) += ctr.o
 obj-$(CONFIG_CRYPTO_KEYWRAP) += keywrap.o
+obj-$(CONFIG_CRYPTO_NHPOLY1305) += nhpoly1305.o
 obj-$(CONFIG_CRYPTO_GCM) += gcm.o
 obj-$(CONFIG_CRYPTO_CCM) += ccm.o
 obj-$(CONFIG_CRYPTO_CHACHA20POLY1305) += chacha20poly1305.o