LinuxKPI: add support for crc32_le()

Add support for crc32_le() as a wrapper around crc32_raw().

Sponsored by: The FreeBSD Foundation
Reviewed by: hselasky
Differential Revision: https://reviews.freebsd.org/D29187

(cherry picked from commit 0c7b75f12840a31206ae24acca1f5ee35c8e341d)