UBUNTU: SAUCE: x86/cpufeatures: Add X86_FEATURE_RDS

CVE-2018-3639 (x86)

Add the CPU feature bit CPUID.7.0.EDX[31] which indicates whether the CPU
supports Reduced Data Speculation.

[ tglx: Split it out from a later patch ]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>

[juergh: Use word 16 instead of 18.]
Signed-off-by: Juerg Haefliger <juergh@canonical.com>

arch/x86/include/asm/cpufeatures.h

@@ -289,6 +289,7 @@
 #define X86_FEATURE_SPEC_CTRL		(16*32+26) /* "" Speculation Control (IBRS + IBPB) */
 #define X86_FEATURE_INTEL_STIBP		(16*32+27) /* "" Single Thread Indirect Branch Predictors */
 #define X86_FEATURE_ARCH_CAPABILITIES	(16*32+29) /* IA32_ARCH_CAPABILITIES MSR (Intel) */
+#define X86_FEATURE_RDS			(16*32+31) /* Reduced Data Speculation */
 
 /*
  * BUG word(s)