msm: camera: Add I2C mux control driver

add i2c mux control driver to control i2c bus
The driver will control which camera the i2c
control message will send to. (etc left, right, both)

Change-Id: I592701b8445d6acc8dfc60f81d562ee52dd65971
Signed-off-by: Kevin Chan <ktchan@codeaurora.org>
diff --git a/arch/arm/mach-msm/devices.h b/arch/arm/mach-msm/devices.h
index c4f57ab..78cb73e 100644
--- a/arch/arm/mach-msm/devices.h
+++ b/arch/arm/mach-msm/devices.h
@@ -59,6 +59,7 @@
 extern struct platform_device msm8960_device_qup_i2c_gsbi12;
 extern struct platform_device msm8960_device_qup_spi_gsbi1;
 extern struct platform_device msm8960_gemini_device;
+extern struct platform_device msm8960_device_i2c_mux_gsbi4;
 extern struct platform_device msm8960_device_csiphy0;
 extern struct platform_device msm8960_device_csiphy1;
 extern struct platform_device msm8960_device_csid0;