Add a target-related log function for user messages as it already
exists for other log levels.
Change-Id: I9076677d6451b900332583e748bab3f83df56d3b
Signed-off-by: Marc Schink <dev@zapb.de>
Reviewed-on: https://review.openocd.org/c/openocd/+/8661
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>
Tested-by: jenkins