rtos: zephyr: do not use deprecated symbols name

rtos: zephyr: do not use deprecated symbols name

Zephyr plan to remove openocd specific symbols in favour
of more generic one.

These generic symbols has been introduced in Zephyr 2.6.

Signed-off-by: Julien Massot <julien.massot@iot.bzh>
Change-Id: I89418c9c378fb8b8baa29763fc6f1b6e652dc7ef
Reviewed-on: https://review.openocd.org/c/openocd/+/6844
Tested-by: jenkins
Reviewed-by: Stephanos Ioannidis <root@stephanos.io>
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>