[mlir] Support normalizing memrefs with MemRef_ReinterpretCastOp

This patch enables normalizing memrefs with MemRef_ReinterpretCastOp by
adding MemRefsNormalizable trait in the Op definition.

Signed-off-by: Haruki Imai <imaihal@jp.ibm.com>

Reviewed By: bondhugula

Differential Revision: https://reviews.llvm.org/D107425