When zImage support was added to SPL, the messages were hidden to reduce
code size. However, the wrong config symbol was used. Since this file is
only built when CONFIG_SPL_FRAMEWORK=y, the messages were always hidden.
Use the correct symbol so the messages are printed in U-Boot proper.
Also use IS_ENABLED to drop the #ifdef.
Fixes: 431889d6ad ("spl: zImage support in Falcon mode")
Signed-off-by: Samuel Holland <samuel@sholland.org>