Fix libdfu CRC check for big endian architectures
Fix libdfu CRC check for big endian architectures

dfu_firmware_generate_crc32() generates a uint in the host byte order, the
proper fix is to write the checksum in LE format like the other fields.

hughsie/fwupd,superm1/fwupd,vathpela/fwupd,superm1/fwupd,vathpela/fwupd,fwupd/fwupd,fwupd/fwupd,hughsie/fwupd,vathpela/fwupd,fwupd/fwupd,superm1/fwupd,fwupd/fwupd,vathpela/fwupd,hughsie/fwupd,hughsie/fwupd