Add struct to record dwarf line number state machine.

gdb/ChangeLog:

	* dwarf2read.c (lnp_state_machine): New typedef.
	(lnp_reader_state): New typedef.
	(dwarf_record_line_1): Renamed from dwarf_record_line.
	All callers updated.
	(dwarf_record_line): New function.
	(init_lnp_state_machine): New function.
	(check_line_address): Replace p_record_line parameter with state.
	All callers updated.
	(dwarf_decode_lines_1): Call dwarf_record_line, init_lnp_state_machine.
	Update to record state in lnp_state_machine.