MFC r311649:

Fix the following clang 4.0.0 warning in ngatm's snmp_atm.c:

contrib/ngatm/snmp_atm/snmp_atm.c:173:6: error: logical not is only
applied to the left hand side of this bitwise operator
[-Werror,-Wlogical-not-parentheses]
if (!ifmr.ifm_status & IFM_AVALID) {
^ ~

Obviously, the masking needs to be done before the logical not
operation. Add parentheses to make it so.

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

This commit was generated by cvs2svn to compensate for changes in r146532,
which included commits to RCS files with non-trunk default branches.

Virgin import of NgATM user part 1.2

Virgin import of NgATM user part 1.1