boards: stm32n6: Fix doc in flashing sections

Fix tab by target on Nucleo
Fix duplicate instructions in both boards

Signed-off-by: Erwan Gouriou <erwan.gouriou@st.com>

Author: erwango

boards/st/nucleo_n657x0_q/doc/index.rst

@@ -153,7 +153,7 @@ First, connect the NUCLEO-N657X0-Q to your host computer using the ST-Link USB p
             :board: nucleo_n657x0_q
             :goals: build flash
 
-.. note::
+         .. note::
             For flashing, before powering the board, set the boot pins in the following configuration:
 
             * BOOT0: 0
@@ -165,12 +165,6 @@ First, connect the NUCLEO-N657X0-Q to your host computer using the ST-Link USB p
 
 	    Power off and on the board again.
 
-         Run a serial host program to connect to your board:
-
-.. code-block:: console
-
-   $ minicom -D /dev/ttyACM0
-
       .. group-tab:: Serial Boot Loader (USB)
 
          Additionally, connect the NUCLEO-N657X0-Q to your host computer using the USB port.
@@ -186,10 +180,10 @@ First, connect the NUCLEO-N657X0-Q to your host computer using the ST-Link USB p
          Build and load an application using ``nucleo_n657x0_q/stm32n657xx/sb`` target (you
          can also use the shortened form: ``nucleo_n657x0_q//sb``)
 
-.. zephyr-app-commands::
-   :zephyr-app: samples/hello_world
-   :board: nucleo_n657x0_q
-   :goals: build flash
+         .. zephyr-app-commands::
+            :zephyr-app: samples/hello_world
+            :board: nucleo_n657x0_q
+            :goals: build flash
 
 
 Run a serial host program to connect to your board:

boards/st/stm32n6570_dk/doc/index.rst

@@ -168,12 +168,6 @@ First, connect the STM32N6570_DK to your host computer using the ST-Link USB por
 
 	    Power off and on the board again.
 
-         Run a serial host program to connect to your board:
-
-         .. code-block:: console
-
-            $ minicom -D /dev/ttyACM0
-
       .. group-tab:: Serial Boot Loader (USB)
 
          Additionally, connect the STM32N6570_DK to your host computer using the USB port.