serial/uart_rpmsg: use config option for console registration

Parameter isconsole in uart_rpmsg_init() has two effects: set uart
terminal flags for typical console use and register the device as
/dev/console. These are separate things. The latter might not be
wanted in all cases.

Use the already existing config option CONFIG_RPMSG_UART_CONSOLE to
conditionally register the uart as console device.

Signed-off-by: Maarten Zanders <maarten@zanders.be>

drivers/serial/uart_rpmsg.c

@@ -458,10 +458,12 @@ int uart_rpmsg_init(FAR const char *cpuname, FAR const char *devname,
            UART_RPMSG_DEV_PREFIX, devname);
   uart_register(name, dev);
 
+  #ifdef CONFIG_RPMSG_UART_CONSOLE
   if (dev->isconsole)
     {
       uart_register(UART_RPMSG_DEV_CONSOLE, dev);
     }
+  #endif
 
   return 0;
 }