Convert CONFIG_SHOW_BOOT_PROGRESS to Kconfig

This converts the following to Kconfig:
   CONFIG_SHOW_BOOT_PROGRESS

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/cherryhill_defconfig b/configs/cherryhill_defconfig
index 3cbc949..6ab336f 100644
--- a/configs/cherryhill_defconfig
+++ b/configs/cherryhill_defconfig
@@ -8,6 +8,7 @@
 CONFIG_DEBUG_UART=y
 CONFIG_SMP=y
 CONFIG_GENERATE_MP_TABLE=y
+CONFIG_SHOW_BOOT_PROGRESS=y
 CONFIG_SYS_CONSOLE_INFO_QUIET=y
 CONFIG_DISPLAY_BOARDINFO_LATE=y
 CONFIG_LAST_STAGE_INIT=y