crypto: lib - implement library version of AES in CFB mode

crypto: lib - implement library version of AES in CFB mode

Implement AES in CFB mode using the existing, mostly constant-time
generic AES library implementation. This will be used by the TPM code
to encrypt communications with TPM hardware, which is often a discrete
component connected using sniffable wires or traces.

While a CFB template does exist, using a skcipher is a major pain for
non-performance critical synchronous crypto where the algorithm is known
at compile time and the data is in contiguous buffers with valid kernel
virtual addresses.

Tested-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Reviewed-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Link: https://lore.kernel.org/all/20230216201410.15010-1-James.Bottomley@HansenPartnership.com/
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Tested-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>