spl: Ensure all SPL symbols in Kconfig have some SPL dependency

Tighten up symbol dependencies in a number of places.  Ensure that a SPL
specific option has at least a direct dependency on SPL.  In places
where it's clear that we depend on something more specific, use that
dependency instead.  This means in a very small number of places we can
drop redundant dependencies.

Reported-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/boot/Kconfig b/boot/Kconfig
index 945ef1c..ee0dc90 100644
--- a/boot/Kconfig
+++ b/boot/Kconfig
@@ -626,7 +626,7 @@
 
 config SPL_BOOTSTAGE
 	bool "Boot timing and reported in SPL"
-	depends on BOOTSTAGE
+	depends on BOOTSTAGE && SPL
 	help
 	  Enable recording of boot time in SPL. To make this visible to U-Boot
 	  proper, enable BOOTSTAGE_STASH as well. This will stash the timing