[MLIR][Linalg] Add more arith named ops to linalg

[MLIR][Linalg] Add more arith named ops to linalg

Following up the 'add' named op, here are the remaining basic arithmetic
and maths, including a 'div_unsigned' for integer unsigned values. In the
same pattern as 'matmul_unsigned', the simply named 'div' assumes signed
values and the '_unsigned' variation handles the unsigned values.

It's a bit odd, but there doesn't seem to be a easy way to restrict to
specific types to make 'div_unsigned' only work with integers in the
structured ops framework.

Same as 'add', these have strict semantics regarding casts.

Unary math ops will need some massaging, so I split these ones for now
as I continue working on them.

Differential Revision: https://reviews.llvm.org/D154524