drivers/misc/sgi-gru/grutlbpurge.c: removed duplicated #include

Removed duplicated include <linux/delay.h> in
drivers/misc/sgi-gru/grutlbpurge.c.

Signed-off-by: Huang Weiyi <weiyi.huang@gmail.com>
Cc: Jack Steiner <steiner@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>