Use a single _payload_offset linker-defined variable to locate the

start of the non-prefix blocks in the loaded image, and rely on the
image ordering.  This should make introducing compression much easier.

src/arch/i386/scripts/i386.lds

@@ -215,6 +215,8 @@ SECTIONS {
 
     _load_size		    = . - _load_addr;
 
+    _payload_offset	    = _text16_load_offset;
+
     /*
      * Alignment checks.  ALIGN() can only operate on the location
      * counter, so we set the location counter to each value we want