scripts/gdb: add empty package initialization script

This got lost during the initial merge process: Python requires an
__init__.py script, even if empty, in order to accept a directory as
package.  Add it, this time as a non-empty file.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>