use protobuf_lite druning inference

[NHZlX]

fix #4542

A new "lite" generator parameter was introduced in the protoc（version > 3） for C++ and
Java messages. Example usage:

./protoc --cpp_out=lite:$OUTPUT_PATH foo.proto

so, so we can set MOBILE_INFERENCE in cmake to decide whether or not to use the lite mode in protobuf.

We did test Under this condition：

arm-v7a CMAKE_BUILD_TYPE='MinSizeRel'

• Before optimize

Library	size(kB)
libpaddle_capi_shared.so	7515
libpaddle_capi_shared.so(strip)	2553
libpaddle_capi_whole.a	14418

• After optimize

Library	size(kB)
libpaddle_capi_shared.so	6556
libpaddle_capi_shared.so(strip)	1869
libpaddle_capi_whole.a	12628

[hedaoyuan]

Can avoid modifying proto files? Here are some similar discussions.

[Xreki]

Need to change the linking library here from PROTOBUF_LIBRARY to PROTOBUF_LITE_LIBRARY. And use make VERBOSE=1 to confirm which library you are linking.

[hedaoyuan]

Actually, even the link PROTOBUF_LIBRARY library will only link to the LITE part of it.

[hedaoyuan]

补充一个优化前后的size变化数据吧。