[lib][cksum] remove warnings in lib/cksum
[libc] add a cheezy mechanism to add entropy to the random 'pool'

Really just xors in a bunch of bytes to the current 32bit random seed.
[platform][zynq][spiflash] read the random number out of the OTP area and add it to the random pool
[lib][bio] add crc32 debug command

Checksums a range of a block device.
[project][zybo-test] add lib/cksum