[mlir][tosa] Add lowering for tosa.rescale to linalg.generic
This adds a tosa.apply_scale operation that handles the scaling operation
common to quantized operatons. This scalar operation is lowered
in TosaToStandard.
We use a separate ApplyScale factorization as this is a replicable pattern
within TOSA. ApplyScale can be reused within pool/convolution/mul/matmul
for their quantized variants.
Tests are added to both tosa-to-standard and tosa-to-linalg-on-tensors
that verify each pass is correct.
Reviewed By: silvas
Differential Revision: https://reviews.llvm.org/D98753