kconfig: move CONFIG_CC_OPTIMIZE_LIBS_FOR_SPEED to Kconfig

If this option is enabled, the objects under lib/ directory
are compiled with speed optimization, not size optimization.
(Currently, only used by some Blackfin boards.)

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Acked-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/bf527-ezkit_defconfig b/configs/bf527-ezkit_defconfig
index 3ed77a6..69f6ef7 100644
--- a/configs/bf527-ezkit_defconfig
+++ b/configs/bf527-ezkit_defconfig
@@ -1,2 +1,3 @@
 CONFIG_BLACKFIN=y
 CONFIG_TARGET_BF527_EZKIT=y
+CONFIG_CC_OPTIMIZE_LIBS_FOR_SPEED=y