Do not hard-code the value, since for s390x it will be smaller than
for x86.
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Link: https://lore.kernel.org/r/20230128000650.1516334-4-iii@linux.ibm.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>