unicore32: select generic atomic64_t support

It's required for the core fs/namespace.c and many other basic features.
Signed-off-by: NGuan Xuetao <gxt@mprc.pku.edu.cn>
Signed-off-by: NFengguang Wu <fengguang.wu@intel.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

arch/unicore32/Kconfig

@@ -6,6 +6,7 @@ config UNICORE32
 	select HAVE_DMA_ATTRS
 	select HAVE_KERNEL_GZIP
 	select HAVE_KERNEL_BZIP2
+	select GENERIC_ATOMIC64
 	select HAVE_KERNEL_LZO
 	select HAVE_KERNEL_LZMA
 	select ARCH_HAVE_CUSTOM_GPIO_H