Summary: Functional.h contains many different methods that have a direct, and more efficient, equivalent in LLVM. This revision replaces all usages with the LLVM equivalent, and removes the header. This is part of larger cleanup, pr45513, merging MLIR support facilities into LLVM.
Differential Revision: https://reviews.llvm.org/D78053
A certain number of EDSCs have a named form (e.g. `linalg.matmul`) and a generic form (e.g. `linalg.generic` with matmul traits).
Despite living in different namespaces, using the same name is confusiong in clients.
Rename them as `linalg_matmul` and `linalg_generic_matmul` respectively.