mfd: Remove leftover from discontinued TWL4030 battery patch

The TWL4030_BCI_BATTERY config option originates from a patch to the
omap git tree. However inclusion in linux was seemingly rejected and
the functionality nears inclusion under a different name so this
removes the bits of the old version that made it into the mainline
kernel again.

Signed-off-by: Christoph Egger <siccegge@stud.informatik.uni-erlangen.de>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/include/linux/i2c/twl.h b/include/linux/i2c/twl.h
index 7897f30..9733e9e 100644
--- a/include/linux/i2c/twl.h
+++ b/include/linux/i2c/twl.h
@@ -605,12 +605,7 @@
 #define TWL4030_VAUX3_DEV_GRP		0x1F
 #define TWL4030_VAUX3_DEDICATED		0x22
 
-#if defined(CONFIG_TWL4030_BCI_BATTERY) || \
-	defined(CONFIG_TWL4030_BCI_BATTERY_MODULE)
-	extern int twl4030charger_usb_en(int enable);
-#else
-	static inline int twl4030charger_usb_en(int enable) { return 0; }
-#endif
+static inline int twl4030charger_usb_en(int enable) { return 0; }
 
 /*----------------------------------------------------------------------*/