Kconfig: disambiguate config names for tiny printf

27084c03d36a ("spl: Allow tiny printf() to be controlled in SPL and
TPL") split this option in two for TPL and SPL, but didn't change the
Kconfig names, making them hard to set quickly.

Signed-off-by: Thomas Hebb <tommyhebb@gmail.com>
diff --git a/lib/Kconfig b/lib/Kconfig
index b8a8509..55dedcb 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -96,7 +96,7 @@
 	  set to 1000.
 
 config SPL_USE_TINY_PRINTF
-	bool "Enable tiny printf() version"
+	bool "Enable tiny printf() version in SPL"
 	depends on SPL
 	default y
 	help
@@ -108,7 +108,7 @@
 	  The supported format specifiers are %c, %s, %u/%d and %x.
 
 config TPL_USE_TINY_PRINTF
-	bool "Enable tiny printf() version"
+	bool "Enable tiny printf() version in TPL"
 	depends on TPL
 	default y if SPL_USE_TINY_PRINTF
 	help