The 32 bit CRC polynomial 0xEDB88320 is a good quality very small random number generator. Unfortunately, the simple loop version is also very slow.
CRC32 adds a very modest 104 bytes to the image which is significantly less than the 454 bytes added by the Libc random function.
On a 1 MHz ATtiny85 processor CRC32 takes 0.610 milliseconds to generate the next value which is significantly faster than the 1.947 milliseconds taken by the Libc random function.
On the dieharder tests, CRC32 always fails one test: diehard_rank_32x32.