Arm backend: Update bias quantization range (#15918)

Bias range was [-2147483648, 2147483646] which isn't really symmetric.
This patch changes the range to [-2147483647, 2147483647].

Signed-off-by: Oscar Andersson <[email protected]>

Author: oscarandersson8218

backends/arm/quantizer/arm_quantizer.py

@@ -209,7 +209,7 @@ def get_symmetric_a16w8_quantization_config(
     # 16-bit activation quantization spec
     act_quantization_spec = QuantizationSpec(
         dtype=torch.int16,
-        quant_min=torch.iinfo(torch.int16).min,  # -32768
+        quant_min=torch.iinfo(torch.int16).min + 1,  # -32767
         quant_max=torch.iinfo(torch.int16).max,  # 32767
         qscheme=torch.per_tensor_symmetric,
         is_dynamic=is_dynamic,

backends/arm/quantizer/quantization_config.py

@@ -206,8 +206,8 @@ def _derive_qparams_fn(
                     derived_from=[(input_act, node), (weight, node)],  # type: ignore[list-item]
                     derive_qparams_fn=_derive_qparams_fn,
                     dtype=torch.int32,
-                    quant_min=torch.iinfo(torch.int32).min,
-                    quant_max=torch.iinfo(torch.int32).max - 1,
+                    quant_min=torch.iinfo(torch.int32).min + 1,
+                    quant_max=torch.iinfo(torch.int32).max,
                     qscheme=qscheme,
                     ch_axis=ch_axis,
                 )