crypto/bio/bio_print.c: support hh length modifier in _dopr

crypto/bio/bio_print.c: support hh length modifier in _dopr

Per [1]:

    hh
        Specifies that a following d, i, o, u, x, or X conversion specifier
        applies to a signed char or unsigned char argument

[1] https://pubs.opengroup.org/onlinepubs/9799919799//functions/printf.html

Signed-off-by: Eugene Syromiatnikov <esyr@openssl.org>
Reviewed-by: Saša Nedvědický <sashan@openssl.org>
Reviewed-by: Neil Horman <nhorman@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/28177)