With old "medium" code model, we call a function with a pair of PCALAU12I
and JIRL instructions. The assembler produces something like:
8: 1a00000c pcalau12i $t0, 0
8: R_LARCH_PCALA_HI20 g
c: 4c000181 jirl $ra, $t0, 0
c: R_LARCH_PCALA_LO12 g
The linker generates a "PLT entry" for data without any diagnostic.
If "g" is a data symbol and ld with -shared option, it may load two
instructions in the PLT.
Without -shared option, loongarch_elf_adjust_dynamic_symbol can delete PLT
entry.
For R_LARCH_PCALA_HI20 relocation, linker only generate PLT entry for STT_FUNC
and STT_GNU_IFUNC symbols.
