sparc64: fix out of order spin_lock_irqsave and spin_unlock_restore

sparc64: fix out of order spin_lock_irqsave and spin_unlock_restore

After enabling spinlocks debug option, kernel prints out call trace
suggesting that the function ldom_req_sp_token executes a might_sleep
function while IRQs is disabled. IRQs is disabled because the
spin_lock_irqsave and spin_unlock_irqrestore are out of order.

Normal correct sequence is:

spin_lock_irqsave(ds_dev_list_lock, data_flags)

        LOCK_DS_DEV()/* spin_lock_irqsave(ds_lock, ds_flags) */
        .
        .
        UNLOCK_DS_DEV()/* spin_unlock_irqrestore(ds_lock, ds_flags) */

spin_unlock_irqrestore(ds_dev_list_lock, data_flags)

Out or order sequence:

spin_lock_irqsave(ds_dev_list_lock, data_flags)

        LOCK_DS_DEV()/* spin_lock_irqsave(ds_lock, ds_flags) */

spin_unlock_irqrestore(ds_dev_list_lock, data_flags)

        UNLOCK_DS_DEV()/* spin_unlock_irqrestore(ds_lock, ds_flags) */

The last UNLOCK_DS_DEV() ends up restoring IRQs to disabled state,
because the previous LOCK_DS_DEV() is in irqs_disabled().
To fix the issue, follows the order of irqsave()/irqrestore().

Orabug: 26265190
Orabug: 25421812

Signed-off-by: Thomas Tai <thomas.tai@oracle.com>
Reviewed-by: Aaron Young <aaron.young@oracle.com>