x86: make 64 bit to use amd.c

arch/x86/kernel/cpu/amd.c is now 100% identical to
arch/x86/kernel/cpu/amd_64.c, so use amd.c on 64-bit too
and fix up the namespace impact.

Simplify the Kconfig glue as well.

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/cpu/Makefile b/arch/x86/kernel/cpu/Makefile
index d031f24..510d1bc 100644
--- a/arch/x86/kernel/cpu/Makefile
+++ b/arch/x86/kernel/cpu/Makefile
@@ -10,8 +10,7 @@
 
 obj-$(CONFIG_CPU_SUP_INTEL_32)		+= intel.o
 obj-$(CONFIG_CPU_SUP_INTEL_64)		+= intel_64.o
-obj-$(CONFIG_CPU_SUP_AMD_32)		+= amd.o
-obj-$(CONFIG_CPU_SUP_AMD_64)		+= amd_64.o
+obj-$(CONFIG_CPU_SUP_AMD)		+= amd.o
 obj-$(CONFIG_CPU_SUP_CYRIX_32)		+= cyrix.o
 obj-$(CONFIG_CPU_SUP_CENTAUR_32)	+= centaur.o
 obj-$(CONFIG_CPU_SUP_CENTAUR_64)	+= centaur_64.o