lib/bootmem: tightly couple bootmem_init to bootmem_write_memory_table

In https://review.coreboot.org/25383 people were confused about the
ordering of bootmem calls w.r.t. when entries are exposed to the OS. To
alleviate this add a notion of bootmem being initialized. In addition to
that, only mark bootmem initialized when bootmem_write_memory_table() is
called. Any other calls to bootmem before that will report an error on
the console.

Change-Id: I5bc31f555038ccabb82d902c54f95858679b1695
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/25503
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>

src/lib/coreboot_table.c

@@ -524,11 +524,7 @@ static uintptr_t write_coreboot_table(uintptr_t rom_table_end)
 	}
 #endif
 
-	/* Initialize the memory map at boot time. */
-	bootmem_init();
-
-	/* No other memory areas can be added after the memory table has been
-	 * committed as the entries won't show up in the serialize mem table. */
+	/* Serialize resource map into mem table types (LB_MEM_*) */
 	bootmem_write_memory_table(lb_memory(head));
 
 	/* Record our motherboard */