sata_dwc_460ex: indent an if statement

We shuffled some code around in 8b344485 ('sata_dwc_460ex: move to
generic DMA driver') an accidentally deleted a tab character here.  It
causes a Smatch warning "if statement not indented".

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Tejun Heo <tj@kernel.org>