spi/bfin_spi: fix resources leakage

Re-order setup() a bit so we don't leak memory/dma/gpio resources upon
errors.  Also make sure we don't call kfree() twice on the same object.

Signed-off-by: Daniel Mack <daniel@caiaq.de>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Yi Li <yi.li@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>