dmaengine: mv_xor: Minor coding style fix

Remove the space before the "err_free_dma:" label in mv_xor_channel_add().

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Gregory CLEMENT <gregory.clement@free-electrons.com>
Cc: Marcin Wojtas <mw@semihalf.com>
Reviewed-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>