Avoid taking the address of a packed struct member in mfiutil
Fix a clang 4.0.0 warning about taking the address of a packed member of
struct mfi_evt in mfiutil:
usr.sbin/mfiutil/mfi_evt.c:583:30: error: taking address of packed
member 'members' of class or structure 'mfi_evt' may result in an
unaligned pointer value [-Werror,-Waddress-of-packed-member]
if (parse_locale(optarg, &filter.members.locale) < 0) {
^~~~~~~~~~~~~~~~~~~~~Use a local variable instead, and copy that into the struct.
Reviewed by: jhb
MFC after: 3 days
Differential Revision: https://reviews.freebsd.org/D9069