LoongArch: Select HAVE_DEBUG_KMEMLEAK to support kmemleak

We can see that DEBUG_KMEMLEAK depends on HAVE_DEBUG_KMEMLEAK after
commit b69ec42b ("Kconfig: clean up the long arch list for the
DEBUG_KMEMLEAK config option"), just select HAVE_DEBUG_KMEMLEAK to
support kmemleak on LoongArch.

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>