spi: dw: Don't use devm_kzalloc in master->setup callback

spi: dw: Don't use devm_kzalloc in master->setup callback

device_add() expects that any memory allocated via devm_* API is only
done in the device's probe function.

Fix below boot warning:
WARNING: CPU: 1 PID: 1 at drivers/base/dd.c:286 driver_probe_device+0x2b4/0x2f4()
Modules linked in:
CPU: 1 PID: 1 Comm: swapper/0 Not tainted 3.16.0-10474-g835c90b-dirty #160
[<c0016364>] (unwind_backtrace) from [<c001251c>] (show_stack+0x20/0x24)
[<c001251c>] (show_stack) from [<c04eaefc>] (dump_stack+0x7c/0x98)
[<c04eaefc>] (dump_stack) from [<c0023d4c>] (warn_slowpath_common+0x78/0x9c)
[<c0023d4c>] (warn_slowpath_common) from [<c0023d9c>] (warn_slowpath_null+0x2c/0x34)
[<c0023d9c>] (warn_slowpath_null) from [<c0302c60>] (driver_probe_device+0x2b4/0x2f4)
[<c0302c60>] (driver_probe_device) from [<c0302d90>] (__device_attach+0x50/0x54)
[<c0302d90>] (__device_attach) from [<c0300e60>] (bus_for_each_drv+0x54/0x9c)
[<c0300e60>] (bus_for_each_drv) from [<c0302958>] (device_attach+0x84/0x90)
[<c0302958>] (device_attach) from [<c0301f10>] (bus_probe_device+0x94/0xb8)
[<c0301f10>] (bus_probe_device) from [<c03000c0>] (device_add+0x434/0x4fc)
[<c03000c0>] (device_add) from [<c0342dd4>] (spi_add_device+0x98/0x164)
[<c0342dd4>] (spi_add_device) from [<c03444a4>] (spi_register_master+0x598/0x768)
[<c03444a4>] (spi_register_master) from [<c03446b4>] (devm_spi_register_master+0x40/0x80)
[<c03446b4>] (devm_spi_register_master) from [<c0346214>] (dw_spi_add_host+0x1a8/0x258)
[<c0346214>] (dw_spi_add_host) from [<c0346920>] (dw_spi_mmio_probe+0x1d4/0x294)
[<c0346920>] (dw_spi_mmio_probe) from [<c0304560>] (platform_drv_probe+0x3c/0x6c)
[<c0304560>] (platform_drv_probe) from [<c0302a98>] (driver_probe_device+0xec/0x2f4)
[<c0302a98>] (driver_probe_device) from [<c0302d3c>] (__driver_attach+0x9c/0xa0)
[<c0302d3c>] (__driver_attach) from [<c0300f0c>] (bus_for_each_dev+0x64/0x98)
[<c0300f0c>] (bus_for_each_dev) from [<c0302518>] (driver_attach+0x2c/0x30)
[<c0302518>] (driver_attach) from [<c0302134>] (bus_add_driver+0xdc/0x1f4)
[<c0302134>] (bus_add_driver) from [<c03035c8>] (driver_register+0x88/0x104)
[<c03035c8>] (driver_register) from [<c030445c>] (__platform_driver_register+0x58/0x6c)
[<c030445c>] (__platform_driver_register) from [<c0700f00>] (dw_spi_mmio_driver_init+0x18/0x20)
[<c0700f00>] (dw_spi_mmio_driver_init) from [<c0008914>] (do_one_initcall+0x90/0x1d4)
[<c0008914>] (do_one_initcall) from [<c06d7d90>] (kernel_init_freeable+0x178/0x248)
[<c06d7d90>] (kernel_init_freeable) from [<c04e687c>] (kernel_init+0x18/0xfc)
[<c04e687c>] (kernel_init) from [<c000ecd8>] (ret_from_fork+0x14/0x20)

Reported-by: Thor Thayer <tthayer@opensource.altera.com>
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org