usb: ohci-omap: avoid unused-variable warning

The dead code removal has led to 'need_transceiver' not being
used at all when OTG support is disabled:

drivers/usb/host/ohci-omap.c: In function 'ohci_omap_reset':
drivers/usb/host/ohci-omap.c:99:33: error: unused variable 'need_transceiver' [-Werror=unused-variable]
   99 |         int                     need_transceiver = (config->otg != 0);

Change the #ifdef check into an IS_ENABLED() check to make the
code more readable and let the compiler see where it is used.

Fixes: 8825acd7 ("ARM: omap1: remove dead code")
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

drivers/usb/host/ohci-omap.c

@@ -67,8 +67,6 @@ static void omap_ohci_clock_power(struct ohci_omap_priv *priv, int on)
 	}
 }
 
-#ifdef	CONFIG_USB_OTG
-
 static void start_hnp(struct ohci_hcd *ohci)
 {
 	struct usb_hcd *hcd = ohci_to_hcd(ohci);
@@ -87,8 +85,6 @@ static void start_hnp(struct ohci_hcd *ohci)
 	local_irq_restore(flags);
 }
 
-#endif
-
 /*-------------------------------------------------------------------------*/
 
 static int ohci_omap_reset(struct usb_hcd *hcd)
@@ -111,8 +107,7 @@ static int ohci_omap_reset(struct usb_hcd *hcd)
 	if (config->ocpi_enable)
 		config->ocpi_enable();
 
-#ifdef	CONFIG_USB_OTG
-	if (need_transceiver) {
+	if (IS_ENABLED(CONFIG_USB_OTG) && need_transceiver) {
 		hcd->usb_phy = usb_get_phy(USB_PHY_TYPE_USB2);
 		if (!IS_ERR_OR_NULL(hcd->usb_phy)) {
 			int	status = otg_set_host(hcd->usb_phy->otg,
@@ -129,7 +124,6 @@ static int ohci_omap_reset(struct usb_hcd *hcd)
 		hcd->skip_phy_initialization = 1;
 		ohci->start_hnp = start_hnp;
 	}
-#endif
 
 	omap_ohci_clock_power(priv, 1);