[HIFN]: Endianess fixes

HIFN uses little-endian by default, move cpu_to_le32 conversion to hifn_write_0/
hifn_write_1, add sparse annotations and fix an invalid endian conversion in
hifn_setup_src_desc.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Acked-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>