pwm: pca9685: depends on I2C rather than REGMAP_I2C

REGMAP_I2C is not a visible config option.
Thus make PWM_PCA9685 depend on I2c and then select REGMAP_I2C.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

drivers/pwm/Kconfig

@@ -112,7 +112,8 @@ config PWM_MXS
 
 config PWM_PCA9685
 	tristate "NXP PCA9685 PWM driver"
-	depends on OF && REGMAP_I2C
+	depends on OF && I2C
+	select REGMAP_I2C
 	help
 	  Generic PWM framework driver for NXP PCA9685 LED controller.