runqemu: Do not auto detect graphics if publicvnc is specified
The graphics option auto detection logic added in
7f78bb7a was not
checking if the publicvnc option had been specified, meaning that
it would be ignored and the auto detection result used instead.
Add setting a flag variable in the argument parsing and check
it along with the ones for the other graphics backend options.
Signed-off-by: Scott Murray <scott.murray@konsulko.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>