Enable ClipQuantFusion exclusively on CPU EP (#20627)
### Motivation and Context
The Intel NPU does not support 16-bit int quantized operators.
Consequently, the execution provider removes the
QuantizeLinear/DeQuantizeLinear (Q/DQ) operators from node units and
executes the operation as FP16 in the backend. However, if a Clip
operator was fused into a Q operator in the node unit, the removal of
Q/DQ operators results in inaccuracies because the effect of the
original Clip operators is lost.
Consider the following example:
- FP32 model: -> Op_FP32 -> Clip ->
- QDQ model: -> (DQ-> Op_FP32 -> Q) -> (DQ' -> Clip -> Q') ->
- After ClipQuantFusion: -> (DQ-> Op_FP32 -> Q) -> (DQ' -> Q') ->
- Intel Execution Provider strips Q/DQ: -> Op_FP16 ->
To solve this issue, we have enabled ClipQuantFusion exclusively on the
CPU execution provider.
