Remove the __USE_GNU guard from pthread_setname_np again.

Caused build breakage, but not spotted by TreeHugger:

  external/libnfc-nxp/Linux_x86/phDal4Nfc.c:737:5: error: implicit declaration of function 'pthread_setname_np' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
    pthread_setname_np(pthread_self(), "reader");
    ^

Nice file name.

Change-Id: I102e55718babf4e4f2f2c64066c6a83ed3ac86d3