drm/shmem-helper: Remove duplicate include

./drivers/gpu/drm/drm_gem_shmem_helper.c: linux/module.h is included more than once.

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=4567


Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230320015829.52988-1-jiapeng.chong@linux.alibaba.com