target/s390x/arch_dump: Add arch cleanup function for PV dumps

target/s390x/arch_dump: Add arch cleanup function for PV dumps

PV dumps block vcpu runs until dump end is reached. If there's an
error between PV dump init and PV dump end the vm will never be able
to run again. One example of such an error is insufficient disk space
for the dump file.

Let's add a cleanup function that tries to do a dump end. The dump
completion data is discarded but there's no point in writing it to a
file anyway if there's a possibility that other PV dump data is
missing.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-ID: <20231109120443.185979-4-frankja@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>