libc/string: Fix the minor style issue

Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>

libs/libc/string/lib_strcat.c

@@ -32,9 +32,9 @@
 
 #ifndef CONFIG_ARCH_STRCAT
 #undef strcat /* See mm/README.txt */
-char *strcat(char *dest, const char *src)
+FAR char *strcat(FAR char *dest, FAR const char *src)
 {
-  char *ret   = dest;
+  FAR char *ret = dest;
 
   dest += strlen(dest);
   while (*src != '\0')

libs/libc/string/lib_strtokr.c

@@ -77,8 +77,8 @@
 
 FAR char *strtok_r(FAR char *str, FAR const char *delim, FAR char **saveptr)
 {
-  char *pbegin;
+  FAR char *pbegin;
-  char *pend = NULL;
+  FAR char *pend = NULL;
 
   /* Decide if we are starting a new string or continuing from
    * the point we left off.

libs/libc/string/lib_vikmemcpy.c

@@ -51,12 +51,6 @@
  *
  ****************************************************************************/
 
-/****************************************************************************
- * Configuration definitions.
- ****************************************************************************/
-
-#define CONFIG_MEMCPY_INDEXED_COPY
-
 /****************************************************************************
  * Included Files
  ****************************************************************************/