SPEEDSTEP: write _CST tables

Change-Id: Idb4b57044808918de343d31519768d0986840f01
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Reviewed-on: http://review.coreboot.org/321
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>

src/arch/x86/include/arch/acpigen.h

@@ -66,4 +66,6 @@ int acpigen_write_resourcetemplate_footer(int len);
 int acpigen_write_mainboard_resource_template(void);
 int acpigen_write_mainboard_resources(const char *scope, const char *name);
 
+int get_cst_entries(struct cst_entry **) __attribute__((weak));
+
 #endif