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/zynq_cse_nor_defconfig b/configs/zynq_cse_nor_defconfig
index 21d7dd5..0a6b172 100644
--- a/configs/zynq_cse_nor_defconfig
+++ b/configs/zynq_cse_nor_defconfig
@@ -10,6 +10,7 @@
 CONFIG_SYS_MALLOC_LEN=0x1000
 CONFIG_SYS_CUSTOM_LDSCRIPT=y
 CONFIG_SYS_LDSCRIPT="arch/arm/mach-zynq/u-boot.lds"
+CONFIG_USE_PREBOOT=y
 # CONFIG_BOARD_LATE_INIT is not set
 # CONFIG_DISPLAY_CPUINFO is not set
 CONFIG_SPL_STACK_R=y