CBMEM: Implement cbmem_run_init_hooks() stub

Until we completely can unify early_variables, use these to
handle CBMEM update hooks for both romstage and ramstage.

For x86, CAR_MIGRATE serves the purpose of romstage hooks.

Change-Id: I100ebc0e35e1b7091b4f287ca37f539fd7c9fa7a
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/7876
Reviewed-by: Aaron Durbin <adurbin@google.com>
Tested-by: build bot (Jenkins)

src/arch/riscv/tables.c

@@ -29,10 +29,6 @@
 
 #define MAX_COREBOOT_TABLE_SIZE (8 * 1024)
 
-void cbmem_arch_init(void)
-{
-}
-
 // WTF. this does not agre with the prototype!
 static struct lb_memory *wtf_write_tables(void)
 {
@@ -70,7 +66,3 @@ void write_tables(void)
 {
 	wtf_write_tables();
 }
-
-void cbmem_fail_resume(void)
-{
-}