Backport: Set the correct mask via ohciEnableInt when enabling interrupt

This fix extends rev 39050. When interrupt is disabled via ohicDisableInt
is it removed from hc_PCIIntEnMask. Enabling HUBCHANGE interrupt without
setting this mask was causing the interrupt to be raised but without
code to handle, causing USB to stop issuing next interrupts.

Problem became visible when starting ASUS M2N68-AM SE2 with usb
keyboard and pendrive connected. USB interrupt was not handled correctly
and USB stack was freezing, blocking IRQ5 which also happened
to be IRQ of SATA.

This fixes #111

rom/usb/pciusb/ohcichip.c

@@ -1165,7 +1165,7 @@ static AROS_INTH1(ohciIntCode, struct PCIController *, hc)
             }
             return FALSE;
         }
-        WRITEREG32_LE(hc->hc_RegBase, OHCI_INTEN, OISF_HUBCHANGE);
+        ohciEnableInt(hc, OISF_HUBCHANGE);
         if(intr & OISF_FRAMECOUNTOVER)
         {
             hc->hc_FrameCounter |= 0x7fff;