LoongArch: Set default alignment for functions jumps and loops [PR112919].

LoongArch: Set default alignment for functions jumps and loops [PR112919].

Xi Ruoyao set the alignment rules under LA464 in commit r14-1839,
but the macro ASM_OUTPUT_ALIGN_WITH_NOP was removed in R14-4674,
which affected the alignment rules.

So I set different aligns on LA464 and LA664 again to test the
performance of spec2006, and modify the alignment based on the test
results.

gcc/ChangeLog:

	PR target/112919
	* config/loongarch/loongarch-def.cc (la664_align): Newly defined
	function that sets alignment rules under the LA664 microarchitecture.
	* config/loongarch/loongarch-opts.cc
	(loongarch_target_option_override): If not optimizing for size, set
	the default alignment to what the target wants.
	* config/loongarch/loongarch-tune.h (struct loongarch_align): Add
	new member variables jump and loop.