Rename defconfig to "cyanogenmod_taoshan_defconfig"

In commit https://github.com/freexperia/android_device_sony_taoshan/commit/4e013b08c58b60a4d3500519896fd224069cc200, you have changed TARGET_KERNEL_CONFIG in BoardConfig.mk (line 59) to "cyanogenmod_taoshan_defconfig". This config therefore has to be renamed accordingly.