axen(4): use %zu modifier for size_t in DPRINTF

[Fabian Raetz]

Hi,

this fixes the build with AXEN_DEBUG defined for me.
Trailing whitespace removed while here.

Regards,
Fabian

Index: if_axen.c
===================================================================
RCS file: /cvs/src/sys/dev/usb/if_axen.c,v
retrieving revision 1.9
diff -u -p -r1.9 if_axen.c
--- if_axen.c   22 Dec 2014 02:28:52 -0000      1.9
+++ if_axen.c   12 Jan 2015 17:48:50 -0000
@@ -1032,7 +1032,7 @@ axen_rxeof(struct usbd_xfer *xfer, void 
 
                pkt_hdr = letoh32(*hdr_p);
                pkt_len = (pkt_hdr >> 16) & 0x1fff;
-               DPRINTFN(10,("rxeof: packet#%d, pkt_hdr 0x%08x, pkt_len %d\n", 
+               DPRINTFN(10,("rxeof: packet#%d, pkt_hdr 0x%08x, pkt_len %zu\n",
                   pkt_count, pkt_hdr, pkt_len));
 
                if ((pkt_hdr & AXEN_RXHDR_CRC_ERR) ||