usb: chipidea: add inline for ci_hdrc_host_driver_init if host is not defined

Otherwise, there is a build warning if this header file is included
by non host source file, eg, otg.c.
Signed-off-by: Jun Li <jun.li@nxp.com>
Signed-off-by: Peter Chen <peter.chen@nxp.com>
Link: https://lore.kernel.org/r/20200122014639.22667-3-peter.chen@nxp.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/chipidea/host.h

@@ -20,7 +20,7 @@ static inline void ci_hdrc_host_destroy(struct ci_hdrc *ci)
 
 }
 
-static void ci_hdrc_host_driver_init(void)
+static inline void ci_hdrc_host_driver_init(void)
 {
 
 }