[PATCHv2] gdb/fortran: Use floatformats_ia64_quad for fortran 16-byte floats

[Tom Tromey]

Andrew> Sorry for breaking this.

Thanks!  Don't feel too bad, though, I think the occasional bug like
this is going to creep in.

Andrew> Or maybe we should be even more restrictive, and only use long double
Andrew> format if its the correct length, like:

This seems to make the most sense to me, but I don't actually know
Fortran, so I'm just guessing.

thanks,
Tom