dmaengine: at_hdmac: use tasklet_kill in teardown
dmaengine: at_hdmac: use tasklet_kill in teardown

As discussed in [1] the tasklet_disable is not a proper function for teardown.
We need to ensure irq is disabled, followed by ensuring that don't schedule any
more tasklets and then its safe to use tasklet_kill().

Here in at_hdmac driver we use free_irq() before tasklet_kill(). The free_irq()
will ensure that the irq is disabled and also wait till all scheduled interrupts
are executed by invoking synchronize_irq(). So we need to only do tasklet_kill()
after invoking free_irq()

[1]: http://lwn.net/Articles/588457/

Reported-by: Thomas Gleixner <00e4cf8f46a57000a44449bf9dd8cbbcc209fd2a@linutronix.de>
Acked-by: Nicolas Ferre <45b517be0e5ec6dc3a39715767c1d18e090d39b4@atmel.com>
Reviewed-by: Thomas Gleixner <00e4cf8f46a57000a44449bf9dd8cbbcc209fd2a@linutronix.de>
Signed-off-by: Vinod Koul <5cf69c63beb17bf38d63aa0e923ee8256af0e205@intel.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs