testsuites/benchmarks/*: Address unused parameter warnings

Add "(void) param;" annotation to address unused parameter warnings.
    Found with GCC's warning -Wunused-paramter.

testsuites/benchmarks/dhrystone/dhry_1.c

@@ -80,6 +80,9 @@ int main (int argc, char **argv)
   /* main program, corresponds to procedures        */
   /* Main and Proc_0 in the Ada version             */
 {
+#ifdef __rtems__
+        (void) argc;
+#endif
         One_Fifty       Int_1_Loc;
   REG   One_Fifty       Int_2_Loc;
         One_Fifty       Int_3_Loc;

testsuites/benchmarks/dhrystone/init.c

@@ -37,6 +37,8 @@ int main(int argc, char **argv);
 
 static void Init(rtems_task_argument arg)
 {
+  (void) arg;
+
   char *argv[] = {
     "dhrystone",
     "1000000",

testsuites/benchmarks/linpack/init.c

@@ -37,6 +37,8 @@ int main(int argc, char **argv);
 
 static void Init(rtems_task_argument arg)
 {
+  (void) arg;
+
   char *argv[] = {
     "linpack",
     "10",

testsuites/benchmarks/linpack/linpack-pc.c

@@ -255,6 +255,9 @@ REAL ddot (int n, REAL dx[], int incx, REAL dy[], int incy);
 
 int main (int argc, char **argv)
 {
+#ifdef __rtems__
+	(void) argc;
+#endif
         static REAL aa[200*200],a[200*201],b[200],x[200];       
         REAL cray,ops,total,norma,normx;
         REAL resid,residn,eps,t1,tm2,epsn,x1,x2;

testsuites/benchmarks/whetstone/init.c

@@ -37,6 +37,8 @@ int main(int argc, char **argv);
 
 static void Init(rtems_task_argument arg)
 {
+  (void) arg;
+
   char *argv[] = {
     "whetstone",
     "10000",