Correct comment in libata-sff.c

The filename in the file header is incorrect.
Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/ata/libata-sff.c

 /*
- *  libata-bmdma.c - helper library for PCI IDE BMDMA
+ *  libata-sff.c - helper library for PCI IDE BMDMA
  *
  *  Maintained by:  Jeff Garzik <jgarzik@pobox.com>
  *    		    Please ALWAYS copy linux-ide@vger.kernel.org