remove TARGET_ARCH_LOWMEM (Blefish)

Could be the culprit of bad performance.

https://github.com/Blefish/android_device_huawei_u8800/commit/34b2166f1a143d753997ebe502ac96df93e69d44

Change-Id: I37a3d0764fe25b31c7ddd022af4bfb9fdec1cf39