sys/include/crypto/modes/ccm: specify implem limits

[fjmolinas]

Contribution description

This PR specifys the length limits according to our ccm implementation for plaintext and adata.
See #12362 and #12364 for reference.

Testing procedure

• Verify limits in code:

adata:

RIOT/sys/crypto/modes/ccm.c

Lines 115 to 125 in be0a24e

	if (auth_data_len <= 0xFEFF) {
	/* length (0x0001 ... 0xFEFF) */
	len_encoding = 2;
	auth_data_encoded[1] = auth_data_len & 0xFF;
	auth_data_encoded[0] = (auth_data_len >> 8) & 0xFF;
	}
	else {
	DEBUG("UNSUPPORTED Adata length: %" PRIu32 "\n", auth_data_len);
	return -1;
	}

plaintext:

RIOT/sys/crypto/modes/ccm.c

Line 41 in be0a24e

uint32_t offset;

Issues/PRs references

[aabadie]

This PR adds valid and helpful details about input parameter to the documentation.

ACK and go