ACPICA: Trivial fix to spelling mistake in comment

ACPICA commit 62c3ff46de977456155fdedbd9f294f2ff700520

Fix spelling mistake, "Reseved" -> "Reserved"

Link: https://github.com/acpica/acpica/commit/62c3ff46


Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Erik Schmauss <erik.schmauss@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>