x86: tsc: Remove legacy timer codes

Now that we have converted all x86 boards to use driver model timer,
remove these legacy timer codes in the tsc driver.

Note this also removes the TSC_CALIBRATION_BYPASS Kconfig option,
as it is not needed with driver model.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>