Remove unneeded version.h include from lib/

This patch removes an unneeded include of linux/version.h from
lib/dynamic_debug.c - identified by 'make versioncheck'.
This is the only file in lib/ with this issue.

Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>