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/cm_t35_defconfig b/configs/cm_t35_defconfig
index 82738b2..872b34f 100644
--- a/configs/cm_t35_defconfig
+++ b/configs/cm_t35_defconfig
@@ -1,8 +1,8 @@
 CONFIG_ARM=y
 CONFIG_OMAP34XX=y
 CONFIG_TARGET_CM_T35=y
-CONFIG_SPL=y
 CONFIG_BOOTDELAY=3
+CONFIG_SPL=y
 CONFIG_HUSH_PARSER=y
 CONFIG_SYS_PROMPT="CM-T3x # "
 CONFIG_CMD_BOOTZ=y