crypto: cfb - add support for Cipher FeedBack mode

TPM security routines require encryption and decryption with AES in
CFB mode, so add it to the Linux Crypto schemes.  CFB is basically a
one time pad where the pad is generated initially from the encrypted
IV and then subsequently from the encrypted previous block of
ciphertext.  The pad is XOR'd into the plain text to get the final
ciphertext.

https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation#CFB

Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto/Kconfig

@@ -320,6 +320,14 @@ config CRYPTO_CBC
 	  CBC: Cipher Block Chaining mode
 	  This block cipher algorithm is required for IPSec.
 
+config CRYPTO_CFB
+	tristate "CFB support"
+	select CRYPTO_BLKCIPHER
+	select CRYPTO_MANAGER
+	help
+	  CFB: Cipher FeedBack mode
+	  This block cipher algorithm is required for TPM2 Cryptography.
+
 config CRYPTO_CTR
 	tristate "CTR support"
 	select CRYPTO_BLKCIPHER