VHADD differs from VHSUB at least on A9 - the former reads both operands in...

VHADD differs from VHSUB at least on A9 - the former reads both operands in the second cycle, while the latter reads second operand in first cycle. Introduce new itin classes to catch this behavior. Whether this is true for A8 as well is WIP.

llvm-svn: 100652