Rephrase 'virtio' Arduino menu to be more explicit

Author: ABOSTM

boards.txt

@@ -1602,11 +1602,11 @@ Eval.menu.xserial.none.build.xSerial=-DHAL_UART_MODULE_ENABLED -DHWSERIAL_NONE
 Eval.menu.xserial.disabled=Disabled (no Serial support)
 Eval.menu.xserial.disabled.build.xSerial=
 
-STM32MP1.menu.virtio.disable=Disabled (no /dev/ttyRPMSG0 available)
+STM32MP1.menu.virtio.disable=Disabled (no SerialVirtIO nor /dev/ttyRPMSG0 available)
 STM32MP1.menu.virtio.disable.build.enable_virtio=
-STM32MP1.menu.virtio.generic=/dev/ttyRPMSG0 => 'Serial' supersede U(S)ART
+STM32MP1.menu.virtio.generic=SerialVirtIO (= generic 'Serial') <=> /dev/ttyRPMSG0
 STM32MP1.menu.virtio.generic.build.enable_virtio={build.virtio_flags}
-STM32MP1.menu.virtio.enabled=/dev/ttyRPMSG0 => SerialVirtIO
+STM32MP1.menu.virtio.enabled=SerialVirtIO <=> /dev/ttyRPMSG0
 STM32MP1.menu.virtio.enabled.build.enable_virtio={build.virtio_flags} -DDISABLE_GENERIC_SERIALVIRTIO
 
 STM32MP1.menu.xserial.generic=UART only (generic 'Serial')