implemented hook_interrupt() in PCI code

enabled PCI interrupts
ohci seems to damage something in PCI config -> PCI device enumeration 
does not top with latest device
networking in EmuTOS lost (probably a result of PCI interrupt
implementation)

BaS_gcc/dma/dma.c

@@ -39,7 +39,7 @@
 #error "unknown machine!"
 #endif /* MACHINE_FIREBEE */
 
-//#define DBG_DMA
+#define DBG_DMA
 #ifdef DBG_DMA
 #define dbg(format, arg...) do { xprintf("DEBUG: %s(): " format, __FUNCTION__, ##arg); } while (0)
 #else