[PATCH] SVM: avoid UB in intercept mask definitions

[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/include/asm-x86/hvm/svm/vmcb.h
+++ b/xen/include/asm-x86/hvm/svm/vmcb.h
@@ -55,7 +55,7 @@ enum GenericIntercept1bits
     GENERAL1_INTERCEPT_MSR_PROT      = 1 << 28,
     GENERAL1_INTERCEPT_TASK_SWITCH   = 1 << 29,
     GENERAL1_INTERCEPT_FERR_FREEZE   = 1 << 30,
-    GENERAL1_INTERCEPT_SHUTDOWN_EVT  = 1 << 31
+    GENERAL1_INTERCEPT_SHUTDOWN_EVT  = 1u << 31
 };
 
 /* general 2 intercepts */
@@ -112,7 +112,7 @@ enum CRInterceptBits
     CR_INTERCEPT_CR12_WRITE = 1 << 28,
     CR_INTERCEPT_CR13_WRITE = 1 << 29,
     CR_INTERCEPT_CR14_WRITE = 1 << 30,
-    CR_INTERCEPT_CR15_WRITE = 1 << 31,
+    CR_INTERCEPT_CR15_WRITE = 1u << 31,
 };
 
 
@@ -150,7 +150,7 @@ enum DRInterceptBits
     DR_INTERCEPT_DR12_WRITE = 1 << 28,
     DR_INTERCEPT_DR13_WRITE = 1 << 29,
     DR_INTERCEPT_DR14_WRITE = 1 << 30,
-    DR_INTERCEPT_DR15_WRITE = 1 << 31,
+    DR_INTERCEPT_DR15_WRITE = 1u << 31,
 };
 
 enum VMEXIT_EXITCODE