staging: dgap: Remove version.h header inclusion in dgap_sysfs.c

version.h header inclusion is not necessary as detected by
versioncheck.

Cc: Lidza Louina <lidza.louina@gmail.com>
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>