selftests: drivers/s390x: Add uvdevice tests

Adds some selftests to test ioctl error paths of the uv-uapi.
The Kconfig S390_UV_UAPI must be selected and the Ultravisor facility
must be available. The test can be executed by non-root, however, the
uvdevice special file /dev/uv must be accessible for reading and
writing which may imply root privileges.

./test-uv-device
TAP version 13
1..6
# Starting 6 tests from 3 test cases.
# RUN uvio_fixture.att.fault_ioctl_arg ...
# OK uvio_fixture.att.fault_ioctl_arg
ok 1 uvio_fixture.att.fault_ioctl_arg
# RUN uvio_fixture.att.fault_uvio_arg ...
# OK uvio_fixture.att.fault_uvio_arg
ok 2 uvio_fixture.att.fault_uvio_arg
# RUN uvio_fixture.att.inval_ioctl_cb ...
# OK uvio_fixture.att.inval_ioctl_cb
ok 3 uvio_fixture.att.inval_ioctl_cb
# RUN uvio_fixture.att.inval_ioctl_cmd ...
# OK uvio_fixture.att.inval_ioctl_cmd
ok 4 uvio_fixture.att.inval_ioctl_cmd
# RUN attest_fixture.att_inval_request ...
# OK attest_fixture.att_inval_request
ok 5 attest_fixture.att_inval_request
# RUN attest_fixture.att_inval_addr ...
# OK attest_fixture.att_inval_addr
ok 6 attest_fixture.att_inval_addr
# PASSED: 6 / 6 tests passed.
# Totals: pass:6 fail:0 xfail:0 xpass:0 skip:0 error:0

Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
Acked-by: Janosch Frank <frankja@linux.ibm.com>
Message-Id: <20220510144724.3321985-3-seiden@linux.ibm.com>
Link: https://lore.kernel.org/kvm/20220510144724.3321985-3-seiden@linux.ibm.com/
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>