x86: add arch-specific SFI support

arch/x86/kernel/sfi.c serves the dual-purpose of supporting the
SFI core with arch specific code, as well as a home for the
arch-specific code that uses SFI.

analogous to ACPI, drivers/sfi/Kconfig is pulled in by arch/x86/Kconfig

Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Cc: x86@kernel.org
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 430d5b2..6321afa 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -55,6 +55,7 @@
 obj-$(CONFIG_STACKTRACE)	+= stacktrace.o
 obj-y				+= cpu/
 obj-y				+= acpi/
+obj-$(CONFIG_SFI)		+= sfi.o
 obj-y				+= reboot.o
 obj-$(CONFIG_MCA)		+= mca_32.o
 obj-$(CONFIG_X86_MSR)		+= msr.o