[Yocto 2579]
When set DISTRO to poky-tiny, only ext2 image is created. But
runqemu-internal doesn't set QEMUOPTIONS for ext2 image that make qemu
fail to boot.
Fix it for qemux86 arch since poky-tiny can only build for qemux86 now.
(From OE-Core rev: 5f2f951bdcb6f29e3ece39250715293d92db5f69)
Signed-off-by: Kang Kai <kai.kang@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>