x86, intel_txt: clean up the impact on generic code, unbreak non-x86

Move tboot.h from asm to linux to fix the build errors of intel_txt
patch on non-X86 platforms. Remove the tboot code from generic code
init/main.c and kernel/cpu.c.

Signed-off-by: Shane Wang <shane.wang@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 80d6e9e..6ce0d6f 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -66,6 +66,7 @@
 
 #include <linux/percpu.h>
 #include <linux/crash_dump.h>
+#include <linux/tboot.h>
 
 #include <video/edid.h>
 
@@ -145,8 +146,6 @@
 struct boot_params boot_params;
 #endif
 
-#include <asm/tboot.h>
-
 /*
  * Machine setup..
  */