doc: fix reference to dma application example

When the dpdk-ioat app was renamed to dpdk-dma this example command
was missed, this patch corrects that issue.

Fixes: bb4141d ("examples/dma: rename ioat application example")

Signed-off-by: Conor Walsh <conor.walsh@intel.com>

Author: conorwalsh-intel

doc/guides/sample_app_ug/dma.rst

@@ -45,7 +45,7 @@ The application requires a number of command line options:
 
 .. code-block:: console
 
-    ./<build_dir>/examples/dpdk-ioat [EAL options] -- [-p MASK] [-q NQ] [-s RS] [-c <sw|hw>]
+    ./<build_dir>/examples/dpdk-dma [EAL options] -- [-p MASK] [-q NQ] [-s RS] [-c <sw|hw>]
         [--[no-]mac-updating] [-b BS] [-f FS] [-i SI]
 
 where,