boards/sama5d3-xplained: Fix OHCI clock.

Choose a divider value that matches the description provided within
the same header file.
Include stddef.h to fix compiler errors because NULL is not defined.
Make logs print protocol, vid and pid consistently, (decimal hex hex).

arch/arm/src/sama5/sam_usbhost.c

@@ -26,6 +26,7 @@
 
 #include <stdint.h>
 #include <stdbool.h>
+#include <stddef.h>
 #include <assert.h>
 
 #include <nuttx/usb/usbhost_trace.h>

boards/arm/sama5/sama5d3-xplained/include/board_sdram.h

@@ -92,11 +92,7 @@
 #  define BOARD_CKGR_UCKR_UPLLCOUNT  (15)  /* Maximum value */
 #  define BOARD_CKGR_UCKR_BIASCOUNT  (15)  /* Maximum value */
 
-/* REVISIT:  The divisor of 10 produces a rate that is too high. Division
- * by 5, however, seems to work just fine.  No idea why?
- */
-
-#  define BOARD_UPLL_OHCI_DIV        (5)   /* Divide by 5 */
+#  define BOARD_UPLL_OHCI_DIV        (10)   /* Divide by 10 */
 #endif
 
 /* ADC Configuration

drivers/usbhost/usbhost_enumerate.c

@@ -115,7 +115,7 @@ static inline int usbhost_devdesc(FAR const struct usb_devdesc_s *devdesc,
   id->vid = usbhost_getle16(devdesc->vendor);
   id->pid = usbhost_getle16(devdesc->product);
 
-  uinfo("class:%d subclass:%04x protocol:%04x vid:%d pid:%d\n",
+  uinfo("class:%d subclass:%d protocol:%d vid:%04x pid:%04x\n",
         id->base, id->subclass, id->proto, id->vid, id->pid);
   return OK;
 }