target/s390x: Expose load_psw and get_psw_mask to cpu.h

target/s390x: Expose load_psw and get_psw_mask to cpu.h

Rename to s390_cpu_set_psw and s390_cpu_get_psw_mask at the
same time.  Adjust so that they compile for user-only.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Tested-by: jonathan.albrecht <jonathan.albrecht@linux.vnet.ibm.com>
Tested-by: <ruixin.bao@ibm.com>
Message-Id: <20210615030744.1252385-2-richard.henderson@linaro.org>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>