CF_HASH_MAXBLK too low for HMAC-SHA3

[zerynth]

Hello and kudos for the awesome project.

While investigating a bug report in our platform we think we have found a bug in the hmac implementation.

cf_hmac_init uses temporary buffers k and blk that are initialized at a size of CF_CHASH_MAXBLK=128. However, the block sizes for sha3-224 and sha3-256 are 144 and 136, causing a buffer overflow on the memset at hmac.c:53

A simple fix is setting CF_CHASH_MAXBLK at 144