Check for large (2GB+) block devices support

Signed-off-by: Philippe De Swert <philippe.deswert@jollamobile.com>
Signed-off-by: Marko Saukko <sage@merproject.org>
No need to short WARNING to WARN
Also show comments with errors.

Signed-off-by: Marko Saukko <sage@merproject.org>
Separate the sections with empty lines to increase readability.

Signed-off-by: Marko Saukko <sage@merproject.org>