buildroot

package: add missing empty line after header

Occurrences were searched using [1]:
check-package --include-only PackageHeader $(find * -type f)
and manually fixed to comply to [2].

[1] http://patchwork.ozlabs.org/patch/729669/
[2] http://nightly.buildroot.org/#writing-rules-mk

Signed-off-by: Ricardo Martincoski <ricardo.martincoski@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>