i386: correct division modeling in lujiazui.md

Model the divider in Lujiazui processors as a separate automaton to
significantly reduce the overall model size. This should also result
in improved accuracy, as pipe 0 should be able to accept new
instructions while the divider is occupied.

It is unclear why integer divisions are modeled as if pipes 0-3 are all
occupied. I've opted to keep a single-cycle reservation of all four
pipes together, so GCC should continue trying to pack instructions
around a division accordingly.

Currently top three symbols in insn-automata.o are:

106102 r lujiazui_core_check
106102 r lujiazui_core_transitions
196123 r lujiazui_core_min_issue_delay

This patch shrinks all lujiazui tables to:

3 r lujiazui_decoder_min_issue_delay
20 r lujiazui_decoder_transitions
32 r lujiazui_agu_min_issue_delay
126 r lujiazui_agu_transitions
304 r lujiazui_div_base
352 r lujiazui_div_check
352 r lujiazui_div_transitions
1152 r lujiazui_core_min_issue_delay
1592 r lujiazui_agu_translate
1592 r lujiazui_core_translate
1592 r lujiazui_decoder_translate
1592 r lujiazui_div_translate
3952 r lujiazui_div_min_issue_delay
9216 r lujiazui_core_transitions

This continues the work on reducing i386 insn-automata.o size started
with similar fixes for division and multiplication instructions in
znver.md.

gcc/ChangeLog:

	PR target/87832
	* config/i386/lujiazui.md (lujiazui_div): New automaton.
	(lua_div): New unit.
	(lua_idiv_qi): Correct unit in the reservation.
	(lua_idiv_qi_load): Ditto.
	(lua_idiv_hi): Ditto.
	(lua_idiv_hi_load): Ditto.
	(lua_idiv_si): Ditto.
	(lua_idiv_si_load): Ditto.
	(lua_idiv_di): Ditto.
	(lua_idiv_di_load): Ditto.
	(lua_fdiv_SF): Ditto.
	(lua_fdiv_SF_load): Ditto.
	(lua_fdiv_DF): Ditto.
	(lua_fdiv_DF_load): Ditto.
	(lua_fdiv_XF): Ditto.
	(lua_fdiv_XF_load): Ditto.
	(lua_ssediv_SF): Ditto.
	(lua_ssediv_load_SF): Ditto.
	(lua_ssediv_V4SF): Ditto.
	(lua_ssediv_load_V4SF): Ditto.
	(lua_ssediv_V8SF): Ditto.
	(lua_ssediv_load_V8SF): Ditto.
	(lua_ssediv_SD): Ditto.
	(lua_ssediv_load_SD): Ditto.
	(lua_ssediv_V2DF): Ditto.
	(lua_ssediv_load_V2DF): Ditto.
	(lua_ssediv_V4DF): Ditto.
	(lua_ssediv_load_V4DF): Ditto.