Delete the code handling large constant for PIC.
Modify some comments.
(score_relax_frag): Decrease insn_addr in certain situation.
(s_score_cprestore): Change .cprestore syntax from ".cprestore offset"
to ".cprestore reg, offset".
(my_get_expression): Const operand of some instructions can not be symbol in assembly.
(get_insn_class_from_type): Handle instruction type Insn_internal.
(do_macro_ldst_label): Modify inst.type.
(Insn_PIC): Delete.
* score-inst.h (enum score_insn_type): Add Insn_internal.
* tc-score.c (data_op2): The immediate value in lw is 15 bit signed.
* score-dis.c (print_insn): Correct the error code to print correct PCE instruction disassembly.