gru: expicitly set instruction status to active

Explicitly set GRU instructions to "ACTIVE".  This eliminates the need for
barriers that would have been necessary to prevent reading the instruction
"status" field before the GRU had actually started the instruction.

Signed-off-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>