boot state: schedule static callbacks

Many of the boot state callbacks can be scheduled at compile time.
Therefore, provide a way for a compilation unit to inform the
boot state machine when its callbacks should be called. Each C
module can export the callbacks and their scheduling requirements
without changing the shared boot flow code.

Change-Id: Ibc4cea4bd5ad45b2149c2d4aa91cbea652ed93ed
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/3133
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

src/lib/rmodule.ld

@@ -61,6 +61,10 @@ SECTIONS
 		cpu_drivers = . ;
 		*(.rodata.cpu_driver)
 		ecpu_drivers = . ;
+		_bs_init_begin = .;
+		*(.bs_init)
+		_bs_init_end = .;
+
 		. = ALIGN(4);
 
 		*(.rodata);