crypto: bfin_crc - access crc registers by readl and writel functions

Move architecture independant crc header file out of the blackfin folder.

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>