[patch] dsp56k: prevent a harmless underflow

[Dan Carpenter]

There is a mistake here where we don't allow "len" to be zero but we
allow negative lengths.  It's basically harmless in this case, but the
underflow makes my static checker complain.

Signed-off-by: Dan Carpenter <dan.carpen...@oracle.com>

diff --git a/drivers/char/dsp56k.c b/drivers/char/dsp56k.c
index 8bf70e8..50aa9ba 100644
--- a/drivers/char/dsp56k.c
+++ b/drivers/char/dsp56k.c
@@ -325,7 +325,7 @@ static long dsp56k_ioctl(struct file *file, unsigned int 
cmd,
                        if(get_user(bin, &binary->bin) < 0)
                                return -EFAULT;
                
-                       if (len == 0) {
+                       if (len <= 0) {
                                return -EINVAL;      /* nothing to upload?!? */
                        }
                        if (len > DSP56K_MAX_BINARY_LENGTH) {