MFC r310232:

MFC r310232:

After r310171, the kernel version of sscanf() has format string checking
enabled.  This results in a -Werror warning in mlx4ib:

    sys/dev/mlx4/mlx4_ib/mlx4_ib_sysfs.c:90:22: error: format specifies type 'unsigned long long *' but the argument has type 'u64 *' (aka 'unsigned long *') [-Werror,-Wformat]
            sscanf(buf, "%llx", &sysadmin_ag_val);
                         ~~~~   ^~~~~~~~~~~~~~~~

Change sysadmin_ag_val to unsigned long long to avoid the warning.

Reviewed by:	hselasky
Differential Revision: https://reviews.freebsd.org/D8831