i2c: designware: dw_i2c_init_driver as subsys initcall

There are few drivers which are available on i2c bus but have been initialized
with subsys_initcall. Also as I2C is a bus driver, it should be available as
early as possible.
Signed-off-by: NPratyush Anand <pratyush.anand@st.com>
Signed-off-by: NViresh Kumar <viresh.kumar@st.com>

[wsa: Slightly updated the commit message]
Signed-off-by: NWolfram Sang <w.sang@pengutronix.de>

drivers/i2c/busses/i2c-designware-platdrv.c

@@ -214,7 +214,7 @@ static int __init dw_i2c_init_driver(void)
 {
 	return platform_driver_probe(&dw_i2c_driver, dw_i2c_probe);
 }
-module_init(dw_i2c_init_driver);
+subsys_initcall(dw_i2c_init_driver);
 
 static void __exit dw_i2c_exit_driver(void)
 {