stream_memory: remove peek callback

This is arguably the only case where the callback made sense.

src/input/stream_memory.c

@@ -37,7 +37,6 @@ struct stream_sys_t
 };
 
 static int  Read   ( stream_t *, void *p_read, unsigned int i_read );
-static int  Peek   ( stream_t *, const uint8_t **pp_peek, unsigned int i_read );
 static int  Control( stream_t *, int i_query, va_list );
 static void Delete ( stream_t * );
 
@@ -73,7 +72,6 @@ stream_t *stream_MemoryNew( vlc_object_t *p_this, uint8_t *p_buffer,
     p_sys->i_preserve_memory = i_preserve_memory;
 
     s->pf_read    = Read;
-    s->pf_peek    = Peek;
     s->pf_control = Control;
     s->pf_destroy = Delete;
     s->p_input = NULL;
@@ -162,11 +160,3 @@ static int Read( stream_t *s, void *p_read, unsigned int i_read )
     p_sys->i_pos += i_res;
     return i_res;
 }
-
-static int Peek( stream_t *s, const uint8_t **pp_peek, unsigned int i_read )
-{
-    stream_sys_t *p_sys = s->p_sys;
-    int i_res = __MIN( i_read, p_sys->i_size - p_sys->i_pos );
-    *pp_peek = p_sys->p_buffer + p_sys->i_pos;
-    return i_res;
-}