drivers/dma/sirf-dma.c: fix usage of devm functions

Fix some problems with the use of devm_ functions.

devm_kzalloc: devm_kfree is not needed

devm_ioremap: iounmap should not be used, no free is needed

devm_request_irq: the devm_free_irq is followed by irq_dispose_mapping.  I
don't know if it is safe to move the freeing of the irq in this case, so I
have just un-devm'd this function, since the implicit freeing is never
taken advantage of.

In the original code failure of of_address_to_resource jumped to free_mem,
but should have jumped to irq_dispose, since irq_of_parse_and_map has
completed at this point.

In the original code unmap_mem was after irq_dispose, but it should have
been before, again since irq_of_parse_and_map has completed at this point.

One of these problems was found using the following semantic match:
(http://coccinelle.lip6.fr/

)

// <smpl>
@@
expression x;
@@

*x = devm_ioremap(...)
...
iounmap(x);
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Acked-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>