building "make omnibus_f4sd_default" with gcc 8.2.1 failes with:
hardfault_log.c:315:7: error: 'strncat' specified bound 30 equals destination size
gcc8 introduced -Wstringop-truncation, which will warn about NULL terminator
truncation.
This patch fixes two similar issues:
- strncpy() makes no sense if we want to copy without NULL terminator
- strncat() needs space to append the NULL terminator
fixes#12283
