gdb/typeprint.h: reorder struct declaration

Move the declaration of struct type_print_raw_options before struct
print_offset_data to ease upcoming changes.  This is a helper commit
intended to make it easier to build a print_offset_data object from
configurations given by a type_print_raw_options.

gdb/ChangeLog:

	* typeprint.h (struct type_print_options): Move before
	  print_offset_data.