meson: Do not use GLX_USE_TLS on Android.

meson: Do not use GLX_USE_TLS on Android.

The asm code expects a specific kind of implementation, but Android
uses something different (emutls).

Turns out mesa has a fallback with pthread_getspecific, with an
optimizaiton if only a single thread is used. emutls also uses
getspecific, so lets just use the optimized mesa implementation.

Fixes: 20294dceebc "mesa: Enable asm unconditionally, now that gen_matypes is gone."
Reviewed-by: Eric Engestrom <eric.engestrom@intel.com>