include: types.h: toolchain.h: Move TLS macro definition

Move the `Z_THREAD_LOCAL` macro from
`include/zephyr/toolchain/common.h` to `include/zephyr/types.h`.

This is needed since some `syscall.h` files are using TLS but aren't
including `zephyr/toolchain.h` (but they are including
`zephyr/types.h`).

Signed-off-by: Daniel Flodin <daniel.flodin@iar.com>