Remove TLS (squashed commits)

Revert "HACK stay compatible with the emulated TLS register HACK"

This reverts commit 4a37ecb8ad08dc3c6fd1c497646463450fff29e0.

Revert "Replace CONFIG_HAS_TLS_REG with HWCAP_TLS and check for it on V6"

This reverts commit a4b4badfde4f99007ba4733c5be0f4785c493cc3.