The /dev/mem file descriptor can be closed without invalidating the
mappings so close as soon as possible.
munmap() all memory, either on error or from quit.
Change-Id: I9466edd2f43791e64f2dce719957c67728f3ec06
Signed-off-by: Steve Marple <stevemarple@googlemail.com>
Reviewed-on: https://review.openocd.org/c/openocd/+/7047
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>