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/chromebook_speedy_defconfig b/configs/chromebook_speedy_defconfig
index 999dc69..4179e80 100644
--- a/configs/chromebook_speedy_defconfig
+++ b/configs/chromebook_speedy_defconfig
@@ -12,6 +12,7 @@
 CONFIG_SPL_SPI_SUPPORT=y
 CONFIG_DEBUG_UART=y
 # CONFIG_ANDROID_BOOT_IMAGE is not set
+CONFIG_USE_PREBOOT=y
 CONFIG_SILENT_CONSOLE=y
 CONFIG_DEFAULT_FDT_FILE="rk3288-veyron-speedy.dtb"
 # CONFIG_DISPLAY_CPUINFO is not set
@@ -93,7 +94,6 @@
 CONFIG_DISPLAY_ROCKCHIP_EDP=y
 CONFIG_DISPLAY_ROCKCHIP_HDMI=y
 # CONFIG_USE_PRIVATE_LIBGCC is not set
-CONFIG_USE_TINY_PRINTF=y
 CONFIG_CMD_DHRYSTONE=y
 CONFIG_ERRNO_STR=y
 # CONFIG_SPL_OF_LIBFDT is not set