app/pipeline: fix build with gcc 10

GCC 10 defaults to -fno-common, this means a linker error will now be
reported if the same global variable is defined in more than one
compilation unit.

Fixes: 48f31ca50c ("app/pipeline: packet framework benchmark")
Cc: stable@dpdk.org

Signed-off-by: Timothy Redaelli <tredaelli@redhat.com>
Acked-by: Cristian Dumitrescu <cristian.dumitrescu@intel.com>

app/test-pipeline/config.c

@@ -42,8 +42,6 @@
 
 #include "main.h"
 
-struct app_params app;
-
 static const char usage[] = "\n";
 
 void