drm/nouveau/nvenc: remove duplicate include in base.c

'priv.h' included in 'base.c' is duplicated.
Remove all but the first include of priv.h from base.c.

Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: yong yiran <yong.yiran@zte.com.cn>
Reviewed-by: Karol Herbst <kherbst@redhat.com>
Signed-off-by: Karol Herbst <kherbst@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210807032054.642867-1-yong.yiran@zte.com.cn