spi/bfin_spi: return immediately after skipping to next transfer

If there is an error with setting up a transfer, we need to return
immediately rather than trying to continue to process things.  We
already set up the error states for the caller at this point.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>