rtos: rework rtos_create()

To simplify the caller of rtos_create(), convert the code from
jimtcl oriented to OpenOCD commands.

While there, fix inconsistencies in almost every rtos create()
method and reset rtos_auto_detect to better cooperate on run-time
rtos configuration.

Change-Id: I59c443aaed77a48174facdfc86db75d6b28c8480
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/8830
Tested-by: jenkins

src/rtos/linux.c

@@ -1424,7 +1424,7 @@ static int linux_os_create(struct target *target)
 	/*  initialize a default virt 2 phys translation */
 	os_linux->phys_mask = ~0xc0000000;
 	os_linux->phys_base = 0x0;
-	return JIM_OK;
+	return ERROR_OK;
 }
 
 static char *linux_ps_command(struct target *target)