usb: chipidea: delete an useless header include

<linux/phy.h> is for net phy drivers, we don't need it.
Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
Signed-off-by: Peter Chen <peter.chen@nxp.com>

drivers/usb/chipidea/core.c

@@ -62,7 +62,6 @@
 #include <linux/usb/chipidea.h>
 #include <linux/usb/of.h>
 #include <linux/of.h>
-#include <linux/phy.h>
 #include <linux/regulator/consumer.h>
 #include <linux/usb/ehci_def.h>