Fix the opcode for Load and Zero Rightmost Byte (32).

Fixes: c2a5c1d7 ("target/s390x: Implement load-and-zero-rightmost-byte insns")
Reported-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: qemu-stable@nongnu.org
Message-Id: <20220914105750.767697-1-borntraeger@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>