Kconfig: disambiguate config names for tiny printf

27084c03 ("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: NThomas Hebb <tommyhebb@gmail.com>

lib/Kconfig

@@ -96,7 +96,7 @@ config SYS_HZ
 	  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 @@ config SPL_USE_TINY_PRINTF
 	  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