[llvm-readelf/obj] - Stop calling `reportError` in `printArchSpecificInfo()`.

This is related to MIPS. Currently we might report an error and exit,
though there is no problem to report a warning and try to continue dumping
an object. The code uses `MipsGOTParser<ELFT> Parser`, which is isolated
in this method.

Differential revision: https://reviews.llvm.org/D92090