KVM: PPC: Book3S HV: Pass the correct trap argument to kvmhv_commence_exit

KVM: PPC: Book3S HV: Pass the correct trap argument to kvmhv_commence_exit

commit 7e022e717f54897e396504306d0c9b61452adf4e upstream.

In guest_exit_cont we call kvmhv_commence_exit which expects the trap
number as the argument. However r3 doesn't contain the trap number at
this point and as a result we would be calling the function with a
spurious trap number.

Fix this by copying r12 into r3 before calling kvmhv_commence_exit as
r12 contains the trap number.

Fixes: eddb60fb1443
Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>