[PATCH for-4.12 and older] x86/msr: fix handling of MSR_IA32_PERF_{STATUS/CTL} (again)

[Jan Beulich]

X86_VENDOR_* aren't bit masks in the older trees.

Reported-by: James Dingwall <ja...@dingwall.me.uk>
Signed-off-by: Jan Beulich <jbeul...@suse.com>

--- a/xen/arch/x86/msr.c
+++ b/xen/arch/x86/msr.c
@@ -226,7 +226,8 @@ int guest_rdmsr(const struct vcpu *v, ui
          */
     case MSR_IA32_PERF_STATUS:
     case MSR_IA32_PERF_CTL:
-        if ( !(cp->x86_vendor & (X86_VENDOR_INTEL | X86_VENDOR_CENTAUR)) )
+        if ( cp->x86_vendor != X86_VENDOR_INTEL &&
+             cp->x86_vendor != X86_VENDOR_CENTAUR )
             goto gp_fault;
 
         *val = 0;