target-ppc: Altivec 2.07: AES Instructions

target-ppc: Altivec 2.07: AES Instructions

This patch adds the Vector AES instructions introduced in Power ISA
Version 2.07:

   - Vector AES Cipher (vcipher)
   - Vector AES Cipher Last (vcipherlast)
   - Vector AES Inverse Cipher (vncipher)
   - Vector AES Inverse Cipher Last (vncipherlast)
   - Vector AES SubBytes (vsbox)

Note that the implementation of vncipher deviates from the RTL in
ISA V2.07.  However it does match the verbal description in the
third paragraph.  The RTL will be fixed in ISA V2.07B.  The
implementation here has been tested against actual P8 hardware.

Signed-off-by: Tom Musta <tommusta@gmail.com>
Signed-off-by: Alexander Graf <agraf@suse.de>