s390: elflint should check if _GLOBAL_OFFSET_TABLE_ points to .got.

The _GLOBAL_OFFSET_TABLE_ symbol might point to the DT_PLTGOT,
which is in the .got section, even if the symbol itself is
associated with the .got.plt section.

See https://sourceware.org/ml/binutils/2018-07/msg00200.html



Signed-off-by: Mark Wielaard <mark@klomp.org>