buildroot

check-package: check Config.* files

Warn when help text is larger than 72 columns, see [1].
Warn for wrongly indented attributes, see [1].
Warn when the convention of attributes order is not followed, see [2].

[1] http://nightly.buildroot.org/#writing-rules-config-in
[2] http://nightly.buildroot.org/#_config_files

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