arch-power: Fix logical instructions

arch-power: Fix logical instructions

Now that 64-bit registers are being used, the instructions
performing comparisons must use the entire 64 bits of the
register operands. Also, most of these instructions need
to determine the nature of the result if the Rc bit is set.
This fixes the following instructions.
  * AND (and[.])
  * OR (or[.])
  * XOR (xor[.])
  * NAND (nand[.])
  * NOR (nor[.])
  * Equivalent (eqv[.])
  * AND with Complement (andc[.])
  * OR with Complement (orc[.])
  * Extend Sign Byte (extsb[.])
  * Extend Sign Halfword (extsh[.])
  * Count Leading Zeros Word (cntlzw[.])
  * Compare Bytes (cmpb)

Change-Id: Ifecb0779fa6e2062d382f9abf8b2cfaf7cea3c96
Signed-off-by: Sandipan Das <sandipan@linux.ibm.com>