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/T1042RDB_PI_SDCARD_defconfig b/configs/T1042RDB_PI_SDCARD_defconfig
index 2bf123d..0e33e35 100644
--- a/configs/T1042RDB_PI_SDCARD_defconfig
+++ b/configs/T1042RDB_PI_SDCARD_defconfig
@@ -1,5 +1,5 @@
 CONFIG_SPL=y
 CONFIG_SYS_EXTRA_OPTIONS="PPC_T1042,T1042RDB_PI,RAMBOOT_PBL,SPL_FSL_PBL,SDCARD"
-+S:CONFIG_PPC=y
-+S:CONFIG_MPC85xx=y
-+S:CONFIG_TARGET_T104XRDB=y
+CONFIG_PPC=y
+CONFIG_MPC85xx=y
+CONFIG_TARGET_T104XRDB=y