There is race condition when multi qemu starting with slirp,
add lockfile for each port to avoid problem like:
runqemu - ERROR - Failed to run qemu: qemu-system-x86_64: Could not set up host forwarding rule 'tcp::2323-:23'
[YOCTO #13364]
(From OE-Core rev: ceb3555a40ba06e58914465376aaf41392c12a7c)
(From OE-Core rev: 9f9657683df90c18c1dfc7e65715b134a44a9d5a)
Signed-off-by: Changqing Li <changqing.li@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>