x86/xen: don't indicate DCA support in pv domains

Xen doesn't support DCA (direct cache access) for pv domains. Clear
the corresponding capability indicator.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Juergen Gross <jgross@suse.com>

arch/x86/xen/enlighten_pv.c

@@ -331,6 +331,7 @@ static void __init xen_init_capabilities(void)
 {
 	setup_clear_cpu_cap(X86_BUG_SYSRET_SS_ATTRS);
 	setup_force_cpu_cap(X86_FEATURE_XENPV);
+	setup_clear_cpu_cap(X86_FEATURE_DCA);
 }
 
 static void xen_set_debugreg(int reg, unsigned long val)