Use the error given in the bcm PCI driver

When given an error return it and not just ENXIO as it may contain
information usefule to debug an error.

Sponsored by:	The FreeBSD Foundation

sys/arm/broadcom/bcm2835/bcm2838_pci.c

@@ -536,7 +536,7 @@ bcm_pcib_msi_attach(device_t dev)
 	    INTR_MPSAFE, bcm_pcib_msi_intr, NULL, sc, &sc->msi_intr_cookie);
 	if (error != 0) {
 		device_printf(dev, "error: failed to setup MSI handler.\n");
-		return (ENXIO);
+		return (error);
 	}
 
 	bcm_name = device_get_nameunit(dev);
@@ -547,7 +547,7 @@ bcm_pcib_msi_attach(device_t dev)
 		if (error != 0) {
 			device_printf(dev,
 			"error: failed to register interrupt %d.\n", i);
-			return (ENXIO);
+			return (error);
 		}
 	}
 
@@ -557,7 +557,7 @@ bcm_pcib_msi_attach(device_t dev)
 
 	error = intr_msi_register(dev, xref);
 	if (error != 0)
-		return (ENXIO);
+		return (error);
 
 	mtx_init(&sc->msi_mtx, "bcm_pcib: msi_mtx", NULL, MTX_DEF);