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/cougarcanyon2_defconfig b/configs/cougarcanyon2_defconfig
index b05da76..2fd2b89 100644
--- a/configs/cougarcanyon2_defconfig
+++ b/configs/cougarcanyon2_defconfig
@@ -8,6 +8,7 @@
 CONFIG_SMP=y
 CONFIG_GENERATE_PIRQ_TABLE=y
 CONFIG_GENERATE_MP_TABLE=y
+CONFIG_SHOW_BOOT_PROGRESS=y
 CONFIG_USE_BOOTARGS=y
 CONFIG_BOOTARGS="root=/dev/sdb3 init=/sbin/init rootwait ro"
 CONFIG_SYS_CONSOLE_INFO_QUIET=y