Operator argument consistency improvement.

Add values attribute to CONST operator.
Remove stale references to input tensor 0 and 1.
Remove out_t types where in and out are guaranteed
to be the same type.

Signed-off-by: Eric Kunze <eric.kunze@arm.com>
Change-Id: I75a8eb4dee67afbee3652d9e937aa0b82318dbd0