clocksource: Change __ARCH_HAS_CLOCKSOURCE_DATA to a CONFIG option

The machinery for __ARCH_HAS_CLOCKSOURCE_DATA assumed a file in
asm-generic would be the default for architectures without their own
file in asm/, but that is not how it works.

Replace it with a Kconfig option instead.

Link: http://lkml.kernel.org/r/4E288AA6.7090804@zytor.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Andy Lutomirski <luto@mit.edu>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Tony Luck <tony.luck@intel.com>
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index da34972..c1e41bc 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -93,6 +93,10 @@
 config GENERIC_CLOCKEVENTS
 	def_bool y
 
+config ARCH_CLOCKSOURCE_DATA
+	def_bool y
+	depends on X86_64
+
 config GENERIC_CLOCKEVENTS_BROADCAST
 	def_bool y
 	depends on X86_64 || (X86_32 && X86_LOCAL_APIC)