rockchip: binman: Support use of crc32 hash for FIT images

rockchip: binman: Support use of crc32 hash for FIT images

Use of SHA256 checksum validation on ARMv7 SoCs can be very time
consuming compared to when used on a ARMv8 SoC with Crypto Extensions.

Add support for use of the much faster CRC32 hash algo when SHA256 is
not supported in SPL. Also use FIT_HASH_ALGO to simplify the ifdefs when
no known hash algo has been compiled.

Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
Reviewed-by: Quentin Schulz <quentin.schulz@cherry.de>