[SPARC] envctrl: implement ->unlocked_ioctl and ->compat_ioctl

all the ioctls in the driver are 32bit compat clean and don't need BKL,
so we can switch it to ->unlocked_ioctl and ->compat_ioctl trivially.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>