powerpc/kvm: sldi should be sld

Since we are taking a registers, this should never have been an sldi.
Talking to paulus offline, this is the correct fix.

Was introduced by:
 commit 19ccb76a
 Author: Paul Mackerras <paulus@samba.org>
 Date:   Sat Jul 23 17:42:46 2011 +1000

Talking to paulus, this shouldn't be a literal.

Signed-off-by: Michael Neuling <mikey@neuling.org>
CC: <stable@kernel.org> [v3.2+]
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>