yoda: Properly check for opts with default value being unset

Signed-off-by: Pavel Emelyanov <xemul@sacred.ru>
yoda: Fix formatting of generated choices

Signed-off-by: Pavel Emelyanov <xemul@sacred.ru>
yoda: Don't generate choice enums for non-strings

They just don't make sence.

Signed-off-by: Pavel Emelyanov <xemul@sacred.ru>
yoda: Generate choice int for default value

Signed-off-by: Pavel Emelyanov <xemul@sacred.ru>