Remove unused function fsname_cmp

This function isn't used anywhere. Addressing GCC warining:
/home/jcerny/openscap/src/OVAL/probes/fsdev.c:77:12: warning:‘fsname_cmp’ defined but not used [-Wunused-function]
 static int fsname_cmp(const void *a, const void *b)
            ^~~~~~~~~~

Author: jan-cerny

src/OVAL/probes/fsdev.c

@@ -73,14 +73,6 @@ static int fsdev_cmp(const void *a, const void *b)
 	return memcmp(a, b, sizeof(dev_t));
 }
 
-/**
- * Compare two strings.
- */
-static int fsname_cmp(const void *a, const void *b)
-{
-	return strcmp(a, b);
-}
-
 #if defined(__linux__) || defined(_AIX)
 
 #define DEVID_ARRAY_SIZE 16