Kconfig: Move CONFIG_BOOTSTAGE to Kconfig

Move CONFIG_BOOT_STAGE and its associated options to Kconfig. Adjust
existing users and code.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/x86/cpu/cpu.c b/arch/x86/cpu/cpu.c
index ed7905c..a9ca50b 100644
--- a/arch/x86/cpu/cpu.c
+++ b/arch/x86/cpu/cpu.c
@@ -163,7 +163,7 @@
 int __weak x86_cleanup_before_linux(void)
 {
 #ifdef CONFIG_BOOTSTAGE_STASH
-	bootstage_stash((void *)CONFIG_BOOTSTAGE_STASH,
+	bootstage_stash((void *)CONFIG_BOOTSTAGE_STASH_ADDR,
 			CONFIG_BOOTSTAGE_STASH_SIZE);
 #endif