MFC r311811:

MFC r311811:

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
Differential Revision:	https://reviews.freebsd.org/D9069