x86: Add basic support for broadwell

This adds the broadwell architecture, with the CPU driver and some useful
header files.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 1a9fa40..0b30883 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -34,6 +34,7 @@
 
 # platform-specific options below
 source "arch/x86/cpu/baytrail/Kconfig"
+source "arch/x86/cpu/broadwell/Kconfig"
 source "arch/x86/cpu/coreboot/Kconfig"
 source "arch/x86/cpu/ivybridge/Kconfig"
 source "arch/x86/cpu/qemu/Kconfig"