Revert "serial: 8250: Let serial core initialise spin lock"

Revert "serial: 8250: Let serial core initialise spin lock"

This reverts commit 679193b7baf8d88e41cbeb397ca17f797654947d.

It appears that in QEmu the lock has been initialised differently
(it wasn't obvious on real hardware during testing). Let's
revert the change until the better approach will be developed.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200802111612.36189-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>