bsps/powerpc/motorola_powerpc: Address unused parameter warnings

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

bsps/powerpc/motorola_powerpc/console/polled_io.c

@@ -451,6 +451,8 @@ int debug_tstc(void)
 #define vidmem ((__io_ptr)(ptr_mem_map->isa_mem_base+0xb8000))
 
 static void vacuum_putc(u_char c) {
+	(void) c;
+
 	console_global_data.vacuum_sent++;
 }
 
@@ -493,12 +495,16 @@ static int global_index = 0;
 
 static void *__palloc(int s)
 {
+  (void) s;
+
   if (global_index ==( STATIC_LOG_DATA_PAGE_NB - 1) ) return (void*) 0;
   return  (void*) &(log_page_pool [PAGE_SIZE * global_index++]);
 }
 
 static void pfree(void* p)
 {
+  (void) p;
+
   --global_index;
 }
 #endif

bsps/powerpc/motorola_powerpc/start/bspstart.c

@@ -104,6 +104,9 @@ char *save_boot_params(
   char *cmdline_end
 )
 {
+  (void) r4;
+  (void) r5;
+  (void) cmdline_end;
 
   residualCopy = *(RESIDUAL *)r3;
   strncpy(loaderParam, cmdline_start, MAX_LOADER_ADD_PARM);