crypto: bfin_crc - ignore duplicated registration of the same algorithm

in case of multiple crc devices are probed.
Call platform_set_drvdata() before adding new CRC device into the list.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Reviewed-by: Marek Vasut <marex@denx.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>