ARM: OMAP2+: Fix zoom LCD backlight if TWL_CORE is not selected

Otherwise we get:

arch/arm/mach-omap2/board-zoom-display.c:64: undefined reference to `twl_i2c_read_u8'
arch/arm/mach-omap2/board-zoom-display.c:65: undefined reference to `twl_i2c_read_u8'
arch/arm/mach-omap2/board-zoom-display.c:84: undefined reference to `twl_i2c_write_u8'
arch/arm/mach-omap2/board-zoom-display.c:86: undefined reference to `twl_i2c_write_u8'
arch/arm/mach-omap2/board-zoom-display.c:91: undefined reference to `twl_i2c_write_u8'
arch/arm/mach-omap2/board-zoom-display.c:92: undefined reference to `twl_i2c_write_u8'
arch/arm/mach-omap2/board-zoom-display.c:72: undefined reference to `twl_i2c_write_u8'

Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/mach-omap2/board-zoom-display.c

@@ -55,6 +55,7 @@ static void zoom_panel_disable_lcd(struct omap_dss_device *dssdev)
 
 static int zoom_set_bl_intensity(struct omap_dss_device *dssdev, int level)
 {
+#ifdef CONFIG_TWL4030_CORE
 	unsigned char c;
 	u8 mux_pwm, enb_pwm;
 
@@ -90,6 +91,9 @@ static int zoom_set_bl_intensity(struct omap_dss_device *dssdev, int level)
 	c = ((50 * (100 - level)) / 100) + 1;
 	twl_i2c_write_u8(TWL4030_MODULE_PWM1, 0x7F, TWL_LED_PWMOFF);
 	twl_i2c_write_u8(TWL4030_MODULE_PWM1, c, TWL_LED_PWMON);
+#else
+	pr_warn("Backlight not enabled\n");
+#endif
 
 	return 0;
 }