Kconfig: Move SPL settings into their own file

Move the SPL settings into common/spl where most of the SPL code is kept.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/CHIP_defconfig b/configs/CHIP_defconfig
index 19ae280..163157d 100644
--- a/configs/CHIP_defconfig
+++ b/configs/CHIP_defconfig
@@ -6,8 +6,8 @@
 CONFIG_USB0_VBUS_PIN="PB10"
 CONFIG_VIDEO_COMPOSITE=y
 CONFIG_DEFAULT_DEVICE_TREE="sun5i-r8-chip"
-CONFIG_SPL=y
 CONFIG_SYS_EXTRA_OPTIONS="CONS_INDEX=2"
+CONFIG_SPL=y
 # CONFIG_CMD_IMLS is not set
 CONFIG_CMD_DFU=y
 CONFIG_CMD_USB_MASS_STORAGE=y