xvmalloc: please Misra C:2012 Rule 8.2

The cloning from xmalloc.h happened long before Misra work started in
earnest, leading to the missing parameter name having been overlooked
later on.

Fixes: 9102fcd ("mm: introduce xvmalloc() et al and use for grant table allocations")
Signed-off-by: Jan Beulich <[email protected]>
Acked-by: Michal Orzel <[email protected]>
Acked-by: Andrew Cooper <[email protected]>

Author: jbeulich

xen/include/xen/xvmalloc.h

@@ -41,7 +41,7 @@
                              __alignof__(typeof(*(ptr)))))
 
 /* Free any of the above. */
-void xvfree(void *);
+void xvfree(void *va);
 
 /* Free an allocation, and zero the pointer to it. */
 #define XVFREE(p) do { \