staging: r8188eu: turbo scan is always off for r8188eu

Turbo scan is always disabled. Remove the TurboScanOff variable and
related checks.

Acked-by: Michael Straube <straube.linux@gmail.com>
Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Link: https://lore.kernel.org/r/20220102175932.89127-6-martin@kaiser.cx


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>