LoongArch: Select HAVE_ARCH_USERFAULTFD_MINOR in Kconfig

This allocates the VM flag needed to support the userfaultfd minor fault
functionality. See commit 7677f7fd ("userfaultfd: add minor fault
registration mode") for more information.
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

arch/loongarch/Kconfig

@@ -105,6 +105,7 @@ config LOONGARCH
 	select HAVE_ARCH_SECCOMP_FILTER
 	select HAVE_ARCH_TRACEHOOK
 	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
+	select HAVE_ARCH_USERFAULTFD_MINOR if USERFAULTFD
 	select HAVE_ASM_MODVERSIONS
 	select HAVE_CONTEXT_TRACKING_USER
 	select HAVE_C_RECORDMCOUNT