gcc-9: silence 'address-of-packed-member' warning

commit 6f303d60534c46aa1a239f29c321f95c83dda748 upstream.

We already did this for clang, but now gcc has that warning too.  Yes,
yes, the address may be unaligned.  And that's kind of the point.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>