extcon: sm5502: Add I2C dependency to fix build break

This patch add I2C configuration dependency to fix following build break.
If specific kernel build I2C as module, extcon-sm5502 have to depend on
I2C configuration.

	drivers/built-in.o: In function `regmap_smbus_byte_reg_read':
	regmap-i2c.c:(.text+0x5030a): undefined reference to `i2c_smbus_read_byte_data'
	drivers/built-in.o: In function `regmap_smbus_byte_reg_write':
	regmap-i2c.c:(.text+0x50338): undefined reference to `i2c_smbus_write_byte_data'
	drivers/built-in.o: In function `regmap_smbus_word_reg_read':
	regmap-i2c.c:(.text+0x50356): undefined reference to `i2c_smbus_read_word_data'
	drivers/built-in.o: In function `regmap_smbus_word_reg_write':
	regmap-i2c.c:(.text+0x50384): undefined reference to `i2c_smbus_write_word_data'
	drivers/built-in.o: In function `regmap_i2c_read':
	regmap-i2c.c:(.text+0x503cf): undefined reference to `i2c_transfer'
	drivers/built-in.o: In function `regmap_i2c_gather_write':
	regmap-i2c.c:(.text+0x50442): undefined reference to `i2c_transfer'
	drivers/built-in.o: In function `regmap_i2c_write':
	regmap-i2c.c:(.text+0x50474): undefined reference to `i2c_master_send'
	drivers/built-in.o: In function `sm5502_muic_i2c_init':
	extcon-sm5502.c:(.init.text+0x6630): undefined reference to `i2c_register_driver'
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>

drivers/extcon/Kconfig

@@ -72,6 +72,7 @@ config EXTCON_PALMAS
 
 config EXTCON_SM5502
 	tristate "SM5502 EXTCON support"
+	depends on I2C
 	select IRQ_DOMAIN
 	select REGMAP_I2C
 	select REGMAP_IRQ