kconfig: remove meaningless prefixes in defconfig files

Since commit e02ee2548afe (kconfig: switch to single .config
configuration), the prefixes in defconfig files such as "+S:",
"+ST:", etc., are meaningless.

This commit was generated by the following command:

  find configs -name '*_defconfig' | xargs sed -i 's/^+*S*T*://'

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/configs/cairo_defconfig b/configs/cairo_defconfig
index ae1dda2..753d2a5 100644
--- a/configs/cairo_defconfig
+++ b/configs/cairo_defconfig
@@ -1,4 +1,4 @@
 CONFIG_SPL=y
-+S:CONFIG_ARM=y
-+S:CONFIG_OMAP34XX=y
-+S:CONFIG_TARGET_OMAP3_CAIRO=y
+CONFIG_ARM=y
+CONFIG_OMAP34XX=y
+CONFIG_TARGET_OMAP3_CAIRO=y