configs: synquacer: Drop Ext2/4 support by default

Since the U-Boot for the SynQuacer DeveloperBox is designed for
compatible with EDK2 boot, we don't need to support Ext2/4 fs
support by default. Drop it.
Signed-off-by: NMasami Hiramatsu <masami.hiramatsu@linaro.org>

configs/synquacer_developerbox_defconfig

@@ -32,8 +32,6 @@ CONFIG_CMD_MII=y
 CONFIG_CMD_PING=y
 CONFIG_CMD_EFIDEBUG=y
 CONFIG_CMD_RTC=y
-CONFIG_CMD_EXT2=y
-CONFIG_CMD_EXT4=y
 CONFIG_CMD_FAT=y
 CONFIG_CMD_FS_GENERIC=y
 CONFIG_CMD_MTDPARTS=y