Convert CONFIG_ARCH_MISC_INIT to Kconfig

This converts the following to Kconfig:
   CONFIG_ARCH_MISC_INIT

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/am335x_boneblack_vboot_defconfig b/configs/am335x_boneblack_vboot_defconfig
index ac0b2a9..9c12355 100644
--- a/configs/am335x_boneblack_vboot_defconfig
+++ b/configs/am335x_boneblack_vboot_defconfig
@@ -11,6 +11,7 @@
 CONFIG_SYS_EXTRA_OPTIONS="EMMC_BOOT,ENABLE_VBOOT"
 CONFIG_SYS_CONSOLE_INFO_QUIET=y
 CONFIG_VERSION_VARIABLE=y
+CONFIG_ARCH_MISC_INIT=y
 CONFIG_SPL=y
 CONFIG_SPL_STACK_R=y
 CONFIG_SPL_MUSB_NEW_SUPPORT=y