Revert "libs/libc: correct the getrandom(2) prototype"

This reverts commit 8411ef1873.

Signed-off-by: chao.an <anchao@xiaomi.com>
Change-Id: I29e90e01f3b8a0460ee53831d38d96edf7d12ef2

crypto/random_pool.c

@@ -555,21 +555,13 @@ void up_randompool_initialize(void)
  * Input Parameters:
  *   bytes  - Buffer for returned random bytes
  *   nbytes - Number of bytes requested.
- *   flags  - Bit mask that can contain zero or more of the ORed values
- *            together.
  *
  * Returned Value:
- *   On success, getrandom() returns the number of bytes that were copied
- *   to the buffer buf.  This may be less than the number of bytes
- *   requested via buflen if either GRND_RANDOM was specified in flags and
- *   insufficient entropy was present in the random source or the system
- *   call was interrupted by a signal.
-
- *   On error, -1 is returned, and errno is set appropriately.
+ *   None
  *
  ****************************************************************************/
 
-ssize_t getrandom(FAR void *bytes, size_t nbytes, unsigned int flags)
+void getrandom(FAR void *bytes, size_t nbytes)
 {
   int ret;
 
@@ -578,13 +570,5 @@ ssize_t getrandom(FAR void *bytes, size_t nbytes, unsigned int flags)
     {
       rng_buf_internal(bytes, nbytes);
       nxsem_post(&g_rng.rd_sem);
-      ret = nbytes;
     }
-  else
-    {
-      set_errno(-ret);
-      ret = ERROR;
-    }
-
-  return ret;
 }