Add missing I2C6 to i2cPorts

Author: mmontol

src/adafruit_blinka/microcontroller/rockchip/rk3588/pin.py

@@ -241,6 +241,7 @@
     (3, I2C3_SCL_M1, I2C3_SDA_M1),
     (4, I2C4_SCL_M3, I2C4_SDA_M3),
     (5, I2C5_SCL_M3, I2C5_SDA_M3),
+    (6, I2C6_SCL_M3, I2C6_SDA_M3),
     (7, I2C7_SCL_M3, I2C7_SDA_M3),
     (8, I2C8_SCL_M2, I2C8_SDA_M2),
     (8, I2C8_SCL_M4, I2C8_SDA_M4),