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/pine_h64_defconfig b/configs/pine_h64_defconfig
index dd1368a..c840ca0 100644
--- a/configs/pine_h64_defconfig
+++ b/configs/pine_h64_defconfig
@@ -6,12 +6,13 @@
 CONFIG_SUNXI_DRAM_H6_LPDDR3=y
 CONFIG_MMC0_CD_PIN="PF6"
 CONFIG_MMC_SUNXI_SLOT_EXTRA=2
+CONFIG_USB3_VBUS_PIN="PL5"
 # CONFIG_PSCI_RESET is not set
 # CONFIG_SYS_MALLOC_CLEAR_ON_INIT is not set
+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="sun50i-h6-pine-h64"
 CONFIG_USB_EHCI_HCD=y
 CONFIG_USB_OHCI_HCD=y
-CONFIG_USB3_VBUS_PIN="PL5"