1. Remove redundant type casts now that PR673 is implemented.
2. Implement the OUT*ir instructions correctly.  The port number really
   *is* a 16-bit value, but the patterns should only match if the number
   is 0-255.  Update the patterns so they now match.
3. Fix patterns for shifts to reflect that the shift amount is always an
   i8, not an i16 as they were believed to be before.  This previous fib
   stopped working when we started knowing that CL has type i8.
4. Change use of i16i8imm in SH*ri patterns to all be imm.

llvm-svn: 24599