Convert CONFIG_USE_PREBOOT and CONFIG_PREBOOT to Kconfig

This converts the following to Kconfig:
   CONFIG_USE_PREBOOT
   CONFIG_PREBOOT

Both are together in one commit, since otherwise the former causes kconfig
to define the latter, which gives duplicate symbol errors.

Includes a manual fixup for CONFIG_PREBOOT in ids8313_defconfig since the
backslash lands in the wrong place. Similarly with socfpga_vining_fpga.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/arndale_defconfig b/configs/arndale_defconfig
index c1b727e..6f586ba 100644
--- a/configs/arndale_defconfig
+++ b/configs/arndale_defconfig
@@ -9,6 +9,7 @@
 CONFIG_DISTRO_DEFAULTS=y
 CONFIG_FIT=y
 CONFIG_FIT_BEST_MATCH=y
+CONFIG_USE_PREBOOT=y
 CONFIG_SILENT_CONSOLE=y
 CONFIG_CONSOLE_MUX=y
 # CONFIG_SPL_FRAMEWORK is not set