CODEOWNERS: take ownership of PCA9685 PWM driver
Take ownership of the PCA9685 PWM driver.
/drivers/ps2/*xec* @franciscomunoz @sjvasanth1
/drivers/ps2/*npcx* @MulinChao @ChiHuaL
/drivers/pwm/*b91* @andy-liu-telink
+/drivers/pwm/*pca9685* @nixward
/drivers/pwm/*rpi_pico* @burumaj
/drivers/pwm/*rv32m1* @henrikbrixandersen
/drivers/pwm/*sam0* @nzmichaelh
