[PATCH] x86/Intel: avoid UB with NMI watchdog on family 15 CPUs

[Jan Beulich <jbeulich@xxxxxxxx>]

Found by looking for patterns similar to the one Julien did spot in
pci_vtd_quirks().

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/xen/arch/x86/nmi.c
+++ b/xen/arch/x86/nmi.c
@@ -132,7 +132,7 @@ int nmi_active;
 #define P4_ESCR_EVENT_SELECT(N)        ((N)<<25)
 #define P4_CCCR_OVF_PMI0       (1<<26)
 #define P4_CCCR_OVF_PMI1       (1<<27)
-#define P4_CCCR_OVF            (1<<31)
+#define P4_CCCR_OVF            (1u << 31)
 #define P4_CCCR_THRESHOLD(N)   ((N)<<20)
 #define P4_CCCR_COMPLEMENT     (1<<19)
 #define P4_CCCR_COMPARE                (1<<18)