gdb: convert aarch64 to new-style debug macros

gdb: convert aarch64 to new-style debug macros

I haven't tried this on an actual aarch64 machine, but I am able to
exercise it like this:

    (gdb) set debug aarch64
    (gdb) maintenance selftest aa
    Running selftest aarch64-analyze-prologue.
    [aarch64] aarch64_analyze_prologue: prologue analysis gave up addr=0x14 opcode=0xf94013e0
    Running selftest aarch64-process-record.
    Ran 2 unit tests, 0 failed

gdb/ChangeLog:

	* arch/aarch64-insn.h (aarch64_debug_printf): New.
	* arch/aarch64-insn.c: Use aarch64_debug_printf.
	* aarch64-tdep.c: Use aarch64_debug_printf.

Change-Id: Ifdb40e2816ab8e55a9aabb066d1833d9b5a46094