Introduce libspeex_googletts, with more speex code.

libspeex_googletts is a static library, intended for
linking against googletts (vendor/unbundled_google/packages/GoogleTTS).
This removes the need for a separate speex repository in googletts
repo.

Change-Id: I8e129c188bd15b7ea06fab8da6a7cfccb4f202d3
speex: disable neon for arm64

The neon instructions in libspeex/resample_neon.h fail to compile
on arm64:
Error: unknown mnemonic `vld1.16' -- `vld1.16 {d16},[x3]!'
Error: unknown mnemonic `vld1.16' -- `vld1.16 {d20},[x6]!'
Error: unknown mnemonic `vmull.s16' -- `vmull.s16 q0,d16,d20'
Error: unknown mnemonic `vld1.16' -- `vld1.16 {d16,d17,d18,d19},[x3]!'
Error: unknown mnemonic `vld1.16' -- `vld1.16 {d20,d21,d22,d23},[x6]!'
...

Disable neon on arm64 for now.

Change-Id: Ifa2a99696241f53b2d6b25c2cb4330b819699a6f
Merge "speex: disable neon for arm64"
am eaa4765b: Merge "speex: disable neon for arm64"

* commit 'eaa4765b8cc6a6dd5ee0d26dc1b61a1044817f32':
  speex: disable neon for arm64