LoongArch: Reword message for unresolvable relocs

LoongArch: Reword message for unresolvable relocs

For PDE, "recompiling with -fPIE" just makes no sense.

For PIE, "recompiling with -fPIE" makes sense for unresolvable absolute
relocs, but not unresolveable PC-relative relocs: if the reloc is
already PC-relative, the problem is not the reloc is PC-relative or
absolute, but the reloc is not applicable for external symbols.

If we hit an unresolvable reloc in PDE or an unresolvable PC-relative
reloc in PIE, it means the programmer has somehow wrongly instructed the
compiler to treat external symbols as local symbols.  A misuse of
-mdirect-extern-access can cause the issue, so we can suggest
-mno-direct-extern-access.  And in all cases (DSO/PIE/PDE) a mismatching
symbol visibility can also cause the issue, so we should also suggest to
check the visibility.

Signed-off-by: Xi Ruoyao <xry111@xry111.site>