[PATCH] lib: make memchr_inv() compliant with Misra rule 11.8

[Jan Beulich <jbeulich@xxxxxxxx>]

Neither the sole present caller nor the two ones pending (in the AMX/ACE
series on x86) require the casting away of constness.

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

--- a/xen/include/xen/string.h
+++ b/xen/include/xen/string.h
@@ -33,7 +33,7 @@ void *memcpy(void *dest, const void *src
 void *memmove(void *dest, const void *src, size_t n);
 int memcmp(const void *cs, const void *ct, size_t count);
 void *memchr(const void *s, int c, size_t n);
-void *memchr_inv(const void *s, int c, size_t n);
+const void *memchr_inv(const void *s, int c, size_t n);
 
 #include <asm/string.h>
 
--- a/xen/lib/memchr_inv.c
+++ b/xen/lib/memchr_inv.c
@@ -13,13 +13,13 @@
  * returns the address of the first occurrence of a character other than @c,
  * or %NULL if the whole buffer contains just @c.
  */
-void *memchr_inv(const void *s, int c, size_t n)
+const void *memchr_inv(const void *s, int c, size_t n)
 {
        const unsigned char *p = s;
 
        while (n--)
                if ((unsigned char)c != *p++)
-                       return (void *)(p - 1);
+                       return p - 1;
 
        return NULL;
 }