runqemu-internal: set mutual exclusiveness for serial and nographic options
Use "-nographic" option only if "serial" option is not
specified. Otherwise we get below error when
'runqemu <kernel_image> <rootfs_image> serial' is executed,
(snip)
QEMU 2.2.0 monitor - type 'help' for more information
(qemu) qemu-system-aarch64: -serial stdio: cannot use stdio by multiple
character devices
-- CUT --
Signed-off-by: Jagadeesh Krishnanjanappa <jkrishnanjanappa@mvista.com> Signed-off-by: Ross Burton <ross.burton@intel.com>
