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/beelink_x2_defconfig b/configs/beelink_x2_defconfig
index be94695..7c62944 100644
--- a/configs/beelink_x2_defconfig
+++ b/configs/beelink_x2_defconfig
@@ -3,14 +3,13 @@
 CONFIG_SPL=y
 CONFIG_MACH_SUN8I_H3=y
 CONFIG_DRAM_CLK=567
-CONFIG_DRAM_ZQ=3881979
 CONFIG_MMC_SUNXI_SLOT_EXTRA=2
-CONFIG_DEFAULT_DEVICE_TREE="sun8i-h3-beelink-x2"
 # CONFIG_SYS_MALLOC_CLEAR_ON_INIT is not set
-CONFIG_CONSOLE_MUX=y
+CONFIG_USE_PREBOOT=y
 # CONFIG_CMD_FLASH is not set
 # CONFIG_SPL_DOS_PARTITION is not set
 # CONFIG_SPL_EFI_PARTITION is not set
+CONFIG_DEFAULT_DEVICE_TREE="sun8i-h3-beelink-x2"
 CONFIG_SUN8I_EMAC=y
 CONFIG_USB_EHCI_HCD=y
 CONFIG_SYS_USB_EVENT_POLL_VIA_INT_QUEUE=y