Fix the following warning by initializing necessary fields in the dma_device
structure.

------------[ cut here ]------------
WARNING: CPU: 0 PID: 1 at drivers/dma/dmaengine.c:863 dma_async_device_register+0x2b4/0x4f0()
this driver doesn't support generic slave capabilities reporting
Modules linked in:
CPU: 0 PID: 1 Comm: swapper Not tainted 4.0.0-rc5+ #10
Hardware name: Sharp-Collie
[<c0105cd8>] (unwind_backtrace) from [<c0103ef8>] (show_stack+0x10/0x14)
[<c0103ef8>] (show_stack) from [<c010e9b8>] (warn_slowpath_common+0x74/0xac)
[<c010e9b8>] (warn_slowpath_common) from [<c010ea20>] (warn_slowpath_fmt+0x30/0x40)
[<c010ea20>] (warn_slowpath_fmt) from [<c02956fc>] (dma_async_device_register+0x2b4/0x4f0)
[<c02956fc>] (dma_async_device_register) from [<c0296a9c>] (sa11x0_dma_probe+0x21c/0x358)
[<c0296a9c>] (sa11x0_dma_probe) from [<c02c52c0>] (platform_drv_probe+0x30/0x94)
[<c02c52c0>] (platform_drv_probe) from [<c02c39bc>] (driver_probe_device+0x84/0x234)
[<c02c39bc>] (driver_probe_device) from [<c02c3c4c>] (__driver_attach+0x98/0x9c)
[<c02c3c4c>] (__driver_attach) from [<c02c1f9c>] (bus_for_each_dev+0x74/0xa4)
[<c02c1f9c>] (bus_for_each_dev) from [<c02c3230>] (bus_add_driver+0x13c/0x1e8)
[<c02c3230>] (bus_add_driver) from [<c02c4260>] (driver_register+0x78/0xf8)
[<c02c4260>] (driver_register) from [<c0100624>] (do_one_initcall+0x84/0x1f4)
[<c0100624>] (do_one_initcall) from [<c0700e1c>] (kernel_init_freeable+0xf8/0x1b4)
[<c0700e1c>] (kernel_init_freeable) from [<c040a920>] (kernel_init+0x8/0xf0)
[<c040a920>] (kernel_init) from [<c01013a8>] (ret_from_fork+0x14/0x2c)
---[ end trace e188b8fe0e782e75 ]---

Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>