sapi: Make Configuration read-only

The Configuration is now read-only and must be statically initialized
via confdefs.h or similar.

cpukit/sapi/include/confdefs.h

@@ -2316,7 +2316,7 @@ rtems_fs_init_functions_t    rtems_fs_init_helper =
   /**
    *  This is the primary Configuration Table for this application.
    */
-  rtems_configuration_table Configuration = {
+  const rtems_configuration_table Configuration = {
     CONFIGURE_EXECUTIVE_RAM_SIZE,             /* required RTEMS workspace */
     CONFIGURE_STACK_SPACE_SIZE,               /* required stack space */
     CONFIGURE_MAXIMUM_USER_EXTENSIONS,        /* maximum dynamic extensions */

cpukit/sapi/include/rtems/config.h

@@ -222,7 +222,7 @@ typedef struct {
 /**
  *   This is the configuration table generated by confdefs.h.
  */
-extern rtems_configuration_table  Configuration;
+extern const rtems_configuration_table Configuration;
 
 #if defined(RTEMS_MULTIPROCESSING)
   /**