Fix warnings noted in PR build checks:

net/telnet.c:1317:40: warning: result of comparison of constant 256 with expression of type 'uint8_t' (aka 'unsigned char') is always true [-Wtautological-constant-out-of-range-compare]
                      if (priv->td_pending < CONFIG_TELNET_RXBUFFER_SIZE)
                          ~~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~

    time/lib_localtime.c:569:32: warning: sizeof on pointer operation will return size of 'char *' instead of 'char [33]' [-Wsizeof-array-decay]
              sizeof(lsp->fullname - 1) <= strlen(p) + strlen(name))
                     ~~~~~~~~~~~~~ ^

drivers/net/telnet.c

@@ -144,10 +144,10 @@ struct telnet_dev_s
   sem_t             td_exclsem;   /* Enforces mutually exclusive access */
   sem_t             td_iosem;     /* I/O thread will notify that data is available */
   uint8_t           td_state;     /* (See telnet_state_e) */
-  uint8_t           td_pending;   /* Number of valid, pending bytes in the rxbuffer */
   uint8_t           td_offset;    /* Offset to the valid, pending bytes in the rxbuffer */
   uint8_t           td_crefs;     /* The number of open references to the session */
   uint8_t           td_minor;     /* Minor device number */
+  uint16_t          td_pending;   /* Number of valid, pending bytes in the rxbuffer */
 #ifdef CONFIG_TELNET_SUPPORT_NAWS
   uint16_t          td_rows;      /* Number of NAWS rows */
   uint16_t          td_cols;      /* Number of NAWS cols */

libs/libc/time/lib_localtime.c

@@ -566,7 +566,7 @@ static int tzload(FAR const char *name,
     {
       p = TZDIR;
       if (p == NULL ||
-          sizeof(lsp->fullname - 1) <= strlen(p) + strlen(name))
+          FILENAME_MAX <= strlen(p) + strlen(name))
         {
           goto oops;
         }