drm/pl111: Remove unused including <linux/version.h>

Remove including <linux/version.h> that don't need it.

Signed-off-by: Cai Huoqing <caihuoqing@baidu.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210727052107.659-1-caihuoqing@baidu.com