tools/misc: Use const whenever we point to literal strings

literal strings are not meant to be modified. So we should use const
char * rather than char * when we we to store a pointer to them.

Signed-off-by: Julien Grall <jgrall@amazon.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: Wei Liu <wl@xen.org>

tools/misc/xen-detect.c

@@ -44,7 +44,7 @@ enum guest_type {
     XEN_NONE = 3
 };
 
-static char *type;
+static const char *type;
 static char *ver;
 
 static void cpuid(uint32_t idx, uint32_t *regs, int pv_context)

tools/misc/xenhypfs.c

@@ -81,9 +81,9 @@ static int xenhypfs_wr(char *path, char *val)
     return ret;
 }
 
-static char *xenhypfs_type(struct xenhypfs_dirent *ent)
+static const char *xenhypfs_type(struct xenhypfs_dirent *ent)
 {
-    char *res;
+    const char *res;
 
     switch (ent->type) {
     case xenhypfs_type_dir:
@@ -134,7 +134,7 @@ static int xenhypfs_ls(char *path)
     return ret;
 }
 
-static int xenhypfs_tree_sub(char *path, unsigned int depth)
+static int xenhypfs_tree_sub(const char *path, unsigned int depth)
 {
     struct xenhypfs_dirent *ent;
     unsigned int n, i;