Upstream commit "warnings be gone."

Adapted from upstream commit 84333e0475bc911adc16417f4ca327c975cf6c36.
Upstream commit "Turn off debug tags in stagefright modules."

Adapted from upstream commit 0e6858d6aea12fc585a8c7d217c1271878655081.
Upstream commit "Check for ARCH_ARM_HAVE_NEON flag only for ARM arch"

This patch prevents ARM neon code from being included
for Arm64, where ARM is the 2nd architecture.

Adapted from upstream commit db46c2f8ff4b305a217adbbd406a61d10ae71db7.
Upstream commit "AAC encoder: add support for SBR mode selection"

Adapted from upstream commit b97cc6a9a3c81215e365c61b071a932073b56ff2.