LoongArch: bfd: Fix some bugs of howto table R_LARCH_IRELATIVE: For dynamic relocation that does not distinguish between 32/64 bits, size and bitsize set to 8 and 64. R_LARCH_TLS_DESC64: Change size to 8. R_LARCH_SOP_POP_32_S_0_5_10_16_S2: Change src_mask to 0, dst_mask to 0x03fffc1f.