LoongArch: Force relocation for every reference to the global offset table

LoongArch: Force relocation for every reference to the global offset table

Local absolute symbols are resolved at assembly stage and the symbol
value is placed in the relocation addend. But non-zero addend will
cause an assertion failure during linking.

Forces emission of relocations to defer resolution of local abs symbols
until link time.

bfd/

        * elfnn-loongarch.c (loongarch_elf_relax_section): Determine
          absolute symbols in advance to avoid ld crash.

gas/

        * config/tc-loongarch.c (loongarch_force_relocation): New
          function to force relocation.
        * config/tc-loongarch.h (TC_FORCE_RELOCATION): New macros
          to force relocation.
        (loongarch_force_relocation): Function declaration.
        * testsuite/gas/loongarch/localpic.d: New test.
        * testsuite/gas/loongarch/localpic.s: New test.