gdb/tracepoint.c: Don't use printf_vma

I noticed that bfd's printf_vma prints to stdout directly:

  bfd-in2.h:202:#define printf_vma(x) fprintf_vma(stdout,x)

This is a bad idea in gdb, where we should use
gdb_stdout/gdb_stderr/gdb_stdlog, etc., to support redirection.

Eliminate uses of sprintf_vma too while at it.

Tested on Fedora 23, w/ gdbserver.

gdb/ChangeLog:
2016-11-17  Pedro Alves  <palves@redhat.com>

	* tracepoint.c (collection_list::add_memrange): Add gdbarch
	parameter.  Use paddress instead of printf_vma.  Adjust recursive
	calls.
	(collection_list::stringify): Use paddress and phex_nz instead of
	sprintf_vma.  Adjust add_memrange call.
	* tracepoint.h (collection_list::add_memrange): Add gdbarch
	parameter.