USB: EHCI: fix build error in ehci-platform.c under PowerPC

This patch (as1628) fixes a build error in the ehci-platform driver
when compiled for the PowerPC architecture.  The error was introduced
by commit 99f91934 (USB: EHCI: make
ehci-platform a separate driver).

The fix is simple; a few additional header-file #includes are needed.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/ehci-platform.c

@@ -19,6 +19,8 @@
  * Licensed under the GNU/GPL. See COPYING for details.
  */
 #include <linux/kernel.h>
+#include <linux/hrtimer.h>
+#include <linux/io.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/usb.h>