drivers: i2c: remove an unnecessary condition check

Remove an unnecessary condition check in Kconfig.
All the config options already depend on I2C.

Change-Id: Ia8876442652df9f105e862d8c2db394699c81f63
Signed-off-by: Baohong Liu <baohong.liu@intel.com>

drivers/i2c/Kconfig

@@ -26,8 +26,6 @@ menuconfig I2C
 	help
 	Enable I2C Driver Configuration
 
-if I2C
-
 config I2C_DW
 	bool "Design Ware I2C support"
 	depends on I2C
@@ -285,5 +283,3 @@ config I2C_SDA_RX_HOLD
 	The hold time on the data signal after a negative edge of i2c clock
 	while i2c acts as receiver.
 	The unit is i2c module base clock.
-
-endif