doc: platform: cznic: turris-omnia-mcu: Fix sphinx-build warning

Fix sphinx-build warnings
  ERROR: Unexpected indentation.
  WARNING: Block quote ends without a blank line; unexpected unindent
in Documentation/ABI/testing/sysfs-bus-i2c-devices-turris-omnia-mcu.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Link: https://lore.kernel.org/all/20240702174938.04c12aab@canb.auug.org.au/
Fixes: dfa556e4 ("platform: cznic: turris-omnia-mcu: Add support for MCU connected GPIOs")
Tested-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Marek Behún <kabel@kernel.org>
Link: https://lore.kernel.org/r/20240730144924.25552-2-kabel@kernel.orgSigned-off-by: Arnd Bergmann <arnd@arndb.de>

Documentation/ABI/testing/sysfs-bus-i2c-devices-turris-omnia-mcu

@@ -32,9 +32,9 @@ Description:	(RW) The front button on the Turris Omnia router can be
 		interrupt.
 
 		This file switches between these two modes:
-		- "mcu" makes the button press event be handled by the MCU to
-		  change the LEDs panel intensity.
-		- "cpu" makes the button press event be handled by the CPU.
+		 - "mcu" makes the button press event be handled by the MCU to
+		   change the LEDs panel intensity.
+		 - "cpu" makes the button press event be handled by the CPU.
 
 		Format: %s.