make dwarf_expr_frame_base_1 public

make dwarf_expr_frame_base_1 public

This exports dwarf_expr_frame_base_1 so that other code can use it.

gdb/ChangeLog
2014-12-12  Tom Tromey  <tromey@redhat.com>
	    Jan Kratochvil  <jan.kratochvil@redhat.com>

	* dwarf2loc.c (dwarf_expr_frame_base_1): Remove declaration.
	(dwarf_expr_frame_base): Update caller.
	(dwarf_expr_frame_base_1): Rename to ...
	(func_get_frame_base_dwarf_block): ... this and make it public.
	(dwarf2_compile_expr_to_ax, locexpr_describe_location_piece): Update
	callers.
	* dwarf2loc.h (func_get_frame_base_dwarf_block): New declaration.