Title underlines should match the length of the title. Unfortunately
docutils only catches underlines that are too short.
Add some missing empty lines after titles.
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
The MT7621 requires external binary blob being executed during u-boot's
boot-up flow. It's necessary to provide a guide here for users to correctly
build the u-boot.
Reviewed-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
Signed-off-by: Weijie Gao <weijie.gao@mediatek.com>