Because kernel_fpu_begin() and kernel_fpu_end() operations are too
slow, the performance gain of general mode implementation + aes-aesni
is almost all compensated.

The AES-NI support for more modes are implemented as follow:

- Add a new AES algorithm implementation named __aes-aesni without
  kernel_fpu_begin/end()

- Use fpu(<mode>(AES)) to provide kenrel_fpu_begin/end() invoking

- Add <mode>(AES) ablkcipher, which uses cryptd(fpu(<mode>(AES))) to
  defer cryption to cryptd context in soft_irq context.

Now the ctr, lrw, pcbc and xts support are added.

Performance testing based on dm-crypt shows that cryption time can be
reduced to 50% of general mode implementation + aes-aesni implementation.
Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>