usb: gadget: renesas_usbhs: fixup driver compile style

In current renesas-usbhs,
there was inconsistency about the style of kernel module or built-in.
This patch solve it.

[ balbi@ti.com : fix compile issue when building modules ]

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/drivers/usb/renesas_usbhs/Makefile b/drivers/usb/renesas_usbhs/Makefile
index e44984d..bc8aef4 100644
--- a/drivers/usb/renesas_usbhs/Makefile
+++ b/drivers/usb/renesas_usbhs/Makefile
@@ -6,5 +6,10 @@
 
 renesas_usbhs-y			:= common.o mod.o pipe.o fifo.o
 
-renesas_usbhs-$(CONFIG_USB_RENESAS_USBHS_HCD)	+= mod_host.o
-renesas_usbhs-$(CONFIG_USB_RENESAS_USBHS_UDC)	+= mod_gadget.o
+ifneq ($(CONFIG_USB_RENESAS_USBHS_HCD),)
+	renesas_usbhs-y		+= mod_host.o
+endif
+
+ifneq ($(CONFIG_USB_RENESAS_USBHS_UDC),)
+	renesas_usbhs-y		+= mod_gadget.o
+endif