Add support for MLIR to llvm vscale attribute (#67012)

The vscale_range is used for scalabale vector functionality in Arm
Scalable Vector Extension to select the size of vector operation (and I
thnk RISCV has something similar).

This patch adds the base support for the vscale_range attribute to the
LLVM::FuncOp, and the marshalling for translation to LLVM-IR and import
from LLVM-IR to LLVM dialect.

This attribute is intended to be used at higher level MLIR, specified
either by command-line options to the compiler or using compiler
directives (e.g. pragmas or function attributes in the source code) to
indicate the desired range.