boards: arm: Update i.MX8M board documentation

GPIO is now supported, we should advertise it.

Signed-off-by: Guy Morand <[email protected]>

Author: morandg

boards/arm/mimx8mm_evk/doc/index.rst

@@ -68,10 +68,15 @@ features:
 | UART      | on-chip    | serial port-polling;                |
 |           |            | serial port-interrupt               |
 +-----------+------------+-------------------------------------+
+| GPIO      | on-chip    | GPIO output                         |
+|           |            | GPIO input                          |
++-----------+------------+-------------------------------------+
 
 The default configuration can be found in the defconfig file:
 :zephyr_file:`boards/arm/mimx8mm_evk/mimx8mm_evk_defconfig`.
 
+It is recommended to disable peripherals used by the M4 core on the Linux host.
+
 Other hardware features are not currently supported by the port.
 
 Connections and IOs