serial/core: Fix too big allocation for attribute member
serial/core: Fix too big allocation for attribute member

Current code allocates too much data for tty_groups member of uart_port struct,
so fix it.

Signed-off-by: Yoshihiro YUNOMAE <ac8be5af0813417580b5f61951eb565904da1b77@hitachi.com>
Reported-by: Dan Carpenter <ff341aa343d564f9e53e9dcb6996be8c04859a66@oracle.com>
Reviewed-by: Daniel Thompson <4421c302a8f2019ff02452a16ddbdd37770f814c@linaro.org>
Signed-off-by: Greg Kroah-Hartman <4645f7897fd33786a2ee1264d590b3c400559d85@linuxfoundation.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs