Remove the win_type parameter from tui_gen_win_info::reset

Remove the win_type parameter from tui_gen_win_info::reset

tui_gen_win_info::reset has a window type parameter that is only used
for an assertion.  This made sense as a defensive measure when window
creation was more dynamic -- it ensured that one did not make
mistakes.  However, there's no need for it any more, so this removes
it.

gdb/ChangeLog
2019-07-17  Tom Tromey  <tom@tromey.com>

	* tui/tui-source.c (tui_source_window_base::reset): Remove
	win_type parameter.
	* tui/tui-layout.c (make_command_window, make_source_window)
	(make_disasm_window, make_data_window)
	(show_source_disasm_command, show_data, tui_gen_win_info::reset)
	(reset_locator, show_source_or_disasm_and_command): Update.
	* tui/tui-data.h (struct tui_gen_win_info) <reset>: Remove
	win_type parameter.
	(struct tui_source_window_base) <reset>: Likewise.