Revert "ACPI: EC: Use a spin lock without disabing interrupts"

Commit eb9299be ("ACPI: EC: Use a spin lock without disabing
interrupts") introduced an unexpected user-visible change in
behavior, which is a significant CPU load increase when the EC
is in use.

This most likely happens due to increased spinlock contention
and so reducing this effect would require a major rework of the
EC driver locking.  There is no time for this in the current
cycle, so revert commit eb9299be.

Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218511


Reported-by: Dieter Mummenschanz <dmummenschanz@web.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>