kernel: Clear IRR register on software interrupt processing

Fixes a hang that can occur due to an infinite loop of interrupts under
certian conditions.

src/core/kernel/exports/EmuKrnl.cpp

@@ -177,7 +177,9 @@ void CallSoftwareInterrupt(const xboxkrnl::KIRQL SoftwareIrql)
 			HalSystemInterrupts[SoftwareIrql - 4].Trigger(EmuInterruptList[SoftwareIrql - 4]);
 		}
 		break;
-	}
+	}
+
+	HalInterruptRequestRegister ^= (1 << SoftwareIrql);
 }
 
 const DWORD IrqlMasks[] = {