target/s390x: Fix LRA overwriting the top 32 bits on DAT error

target/s390x: Fix LRA overwriting the top 32 bits on DAT error

When a DAT error occurs, LRA is supposed to write the error information
to the bottom 32 bits of R1, and leave the top 32 bits of R1 alone.

Fix by passing the original value of R1 into helper and copying the
top 32 bits to the return value.

Fixes: d8fe4a9c284f ("target-s390: Convert LRA")
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: qemu-stable@nongnu.org
Message-Id: <20230704081506.276055-6-iii@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>