LoongArch: Select ARCH_ENABLE_THP_MIGRATION instead of redefining it

ARCH_ENABLE_THP_MIGRATION is supposed to be selected by arch Kconfig.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

arch/loongarch/Kconfig

@@ -12,6 +12,7 @@ config LOONGARCH
 	select ARCH_DISABLE_KASAN_INLINE
 	select ARCH_ENABLE_MEMORY_HOTPLUG
 	select ARCH_ENABLE_MEMORY_HOTREMOVE
+	select ARCH_ENABLE_THP_MIGRATION if TRANSPARENT_HUGEPAGE
 	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
 	select ARCH_HAS_CPU_FINALIZE_INIT
 	select ARCH_HAS_FORTIFY_SOURCE
@@ -667,10 +668,6 @@ config ARCH_SPARSEMEM_ENABLE
 	  or have huge holes in the physical address space for other reasons.
 	  See <file:Documentation/mm/numa.rst> for more.
 
-config ARCH_ENABLE_THP_MIGRATION
-	def_bool y
-	depends on TRANSPARENT_HUGEPAGE
-
 config ARCH_MEMORY_PROBE
 	def_bool y
 	depends on MEMORY_HOTPLUG