CBMEM: Change declarations for initialization hooks

There are efforts to have bootflows that do not follow a traditional
bootblock-romstage-postcar-ramstage model. As part of that CBMEM
initialisation hooks will need to move from romstage to bootblock.

The interface towards platforms and drivers will change to use one of
CBMEM_CREATION_HOOK() or CBMEM_READY_HOOK(). Former will only be called
in the first stage with CBMEM available.

Change-Id: Ie24bf4e818ca69f539196c3a814f3c52d4103d7e
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/63375
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Raul Rangel <rrangel@chromium.org>

src/lib/program.ld

@@ -24,7 +24,7 @@
 	*(.text);
 	*(.text.*);
 
-#if ENV_RAMSTAGE || ENV_ROMSTAGE || ENV_POSTCAR
+#if ENV_HAS_CBMEM
 	. = ALIGN(ARCH_POINTER_ALIGN_SIZE);
 	_cbmem_init_hooks = .;
 	KEEP(*(.rodata.cbmem_init_hooks_early));