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/Mele_M5_defconfig b/configs/Mele_M5_defconfig
index 2e1f80d..1442318 100644
--- a/configs/Mele_M5_defconfig
+++ b/configs/Mele_M5_defconfig
@@ -2,12 +2,12 @@
 CONFIG_SYS_EXTRA_OPTIONS="SUNXI_GMAC,AHCI,USB_EHCI,STATUSLED=234"
 CONFIG_FDTFILE="sun7i-a20-m5.dtb"
 CONFIG_VIDEO_HDMI=y
-+S:CONFIG_MMC0_CD_PIN="PH1"
-+S:CONFIG_USB1_VBUS_PIN="PH6"
-+S:CONFIG_USB2_VBUS_PIN="PH3"
-+S:CONFIG_ARM=y
-+S:CONFIG_ARCH_SUNXI=y
-+S:CONFIG_MACH_SUN7I=y
-+S:CONFIG_DRAM_CLK=432
-+S:CONFIG_DRAM_ZQ=122
-+S:CONFIG_DRAM_EMR1=4
+CONFIG_MMC0_CD_PIN="PH1"
+CONFIG_USB1_VBUS_PIN="PH6"
+CONFIG_USB2_VBUS_PIN="PH3"
+CONFIG_ARM=y
+CONFIG_ARCH_SUNXI=y
+CONFIG_MACH_SUN7I=y
+CONFIG_DRAM_CLK=432
+CONFIG_DRAM_ZQ=122
+CONFIG_DRAM_EMR1=4