joule.md: Fix i2c bus number in documentation
@@ -124,7 +124,7 @@ LEDs are numbered from 100-103.
| 74 | UART1TX | GPIO UART|
| 75 | I2C2SDA | GPIO I2C |
| 76 | UART1RX | GPIO UART|
-| 77 | I2C1SCL | GPIO I2C |
+| 77 | I2C2SCL | GPIO I2C |
| 78 | UART1RT | GPIO UART|
| 79 | RTC_CLK | GPIO |
| 80 | UART1CT | GPIO UART|
