Fix support for MatMulInteger and ConvInteger Nodes in Onnxruntime MIGraphX EP

[TedThemistokleous]

Viewing code in Onnxruntime for IsUnsupportedOpMode() before we compile in a model

Seeing cases which are handled in MIGraphX correctly but are still marked as not supported in Onnxruntime

• ConvInteger only supporting 4 inputs, where we can support 2 inputs with no biases, or combinations of biases
• MatMulInteger only supporting 2 inputs, which leaves any and all bias

Fix these in the EP. Likely more to follow with this