[PATH RESEND v2 02/10] tty: xuartps: Use spinlock to serialize HW access

Instead of disabling the IRQ, use the spin lock to serialize accesses to the HW. This protects the driver from interference of non-IRQ callbacks with each other and makes the driver more consistent in its serialization method. Signed-off-by: Soren Brinkmann --- v2: - remove unused variable ---

[PATH RESEND v2 02/10] tty: xuartps: Use spinlock to serialize HW access

Instead of disabling the IRQ, use the spin lock to serialize accesses to the HW. This protects the driver from interference of non-IRQ callbacks with each other and makes the driver more consistent in its serialization method. Signed-off-by: Soren Brinkmann --- v2: -