crypto/idea/i_cfb64.c: condition 'n < 0' can never be met after doing 'n = n & 0x07'

crypto/idea/i_cfb64.c: condition 'n < 0' can never be met after doing 'n = n & 0x07'

Resolves: https://scan5.scan.coverity.com/#/project-view/62622/10222?selectedIssue=1689816
Fixes: 5ba9029bc7b3 "Mask *num on entry in deprecated low-level OFB/CFB implementations"
Reviewed-by: Tomas Mraz <tomas@openssl.foundation>
Reviewed-by: Neil Horman <nhorman@openssl.org>
Reviewed-by: Paul Dale <paul.dale@oracle.com>
Reviewed-by: Eugene Syromiatnikov <esyr@openssl.org>
MergeDate: Sat Mar 21 23:50:41 2026
(Merged from https://github.com/openssl/openssl/pull/30500)