Don't use print_insn_XXX in GDB

Don't use print_insn_XXX in GDB

This is a follow-up to

  [PATCH 0/6] Unify the disassembler selection in gdb and objdump
  https://sourceware.org/ml/binutils/2017-05/msg00192.html

that is, opcodes is able to select the right disassembler, so gdb
doesn't have to select them.  Instead, gdb can just use
default_print_insn.  As a result, these print_insn_XXX are not used
out of opcodes, so this patch also moves their declarations from
include/dis-asm.h to opcodes/disassemble.h.  With this change,
GDB doesn't use any print_insn_XXX directly any more.

gdb:

2017-06-14  Yao Qi  <yao.qi@linaro.org>

	* aarch64-tdep.c (aarch64_gdb_print_insn): Call
	default_print_insn instead of print_insn_aarch64.
	* arm-tdep.c (gdb_print_insn_arm): Call
	default_print_insn instead of print_insn_big_arm
	and print_insn_little_arm.
	* i386-tdep.c (i386_print_insn): Call default_print_insn
	instead of print_insn_i386.
	* ia64-tdep.c (ia64_print_insn): Call
	default_print_insn instead of print_insn_ia64.
	* mips-tdep.c (gdb_print_insn_mips): Call
	default_print_insn instead of print_insn_big_mips
	and print_insn_little_mips.
	* spu-tdep.c (gdb_print_insn_spu): Call default_print_insn
	instead of print_insn_spu.

include:

2017-06-14  Yao Qi  <yao.qi@linaro.org>

	* dis-asm.h (print_insn_aarch64): Move it to opcodes/disassemble.h.
	(print_insn_big_arm, print_insn_big_mips): Likewise.
	(print_insn_i386, print_insn_ia64): Likewise.
	(print_insn_little_arm, print_insn_little_mips): Likewise.
	(print_insn_spu): Likewise.

opcodes:

2017-06-14  Yao Qi  <yao.qi@linaro.org>

	* aarch64-dis.c: Include disassemble.h instead of dis-asm.h.
	* arm-dis.c: Likewise.
	* ia64-dis.c: Likewise.
	* mips-dis.c: Likewise.
	* spu-dis.c: Likewise.
	* disassemble.h (print_insn_aarch64): New declaration, moved from
	include/dis-asm.h.
	(print_insn_big_arm, print_insn_big_mips): Likewise.
	(print_insn_i386, print_insn_ia64): Likewise.
	(print_insn_little_arm, print_insn_little_mips): Likewise.