[PATCH] include/linux/usb/usb_phy_gen_xceiv.h: check built-in or module for swithing usb_nop_xceiv_register() implementation

[Chen Gang]

When CONFIG_NOP_USB_XCEIV is as 'm', usb_nop_xceiv_register() will be
exported when the related module is loaded. So for built-in source
code, still need use the empty one.

Or it will can not pass compiling, the related error (for arm, with 
allmodconfig):

  arch/arm/mach-omap2/built-in.o: In function `omap3_evm_init':
  arch/arm/mach-omap2/board-omap3evm.c:703: undefined reference to `usb_nop_xceiv_register'


Signed-off-by: Chen Gang <gang.chen at asianux.com>
---
 include/linux/usb/usb_phy_gen_xceiv.h |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/include/linux/usb/usb_phy_gen_xceiv.h b/include/linux/usb/usb_phy_gen_xceiv.h
index f9a7e7b..8515958 100644
--- a/include/linux/usb/usb_phy_gen_xceiv.h
+++ b/include/linux/usb/usb_phy_gen_xceiv.h
@@ -12,7 +12,8 @@ struct usb_phy_gen_xceiv_platform_data {
 	unsigned int needs_reset:1;
 };
 
-#if IS_ENABLED(CONFIG_NOP_USB_XCEIV)
+#if IS_BUILTIN(CONFIG_NOP_USB_XCEIV) || \
+	(IS_MODULE(CONFIG_NOP_USB_XCEIV) && defined(MODULE))
 /* sometimes transceivers are accessed only through e.g. ULPI */
 extern void usb_nop_xceiv_register(void);
 extern void usb_nop_xceiv_unregister(void);
-- 
1.7.7.6