target/s390x: Rely on unwinding in s390_cpu_tlb_fill

target/s390x: Rely on unwinding in s390_cpu_tlb_fill

We currently set ilen to AUTO, then overwrite that during
unwinding, then overwrite that for the code access case.

This can be simplified to setting ilen to our arbitrary
value for the (undefined) code access case, then rely on
unwinding to overwrite that with the correct value for
the data access case.

Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20191001171614.8405-14-richard.henderson@linaro.org>
Signed-off-by: David Hildenbrand <david@redhat.com>