kf5-networkmanager-qt: correct dependencies comment display conditions
Display the dependencies comment only when network-manager is enabled.
Otherwise, a toolchain configuration change would not make the package
selectable.
Cc: Pierre Ducroquet <pinaraf@pinaraf.info>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>