Properly implement poll_wait() in the LinuxKPI. This prevents direct
use of the linux_poll_wakeup() function from unsafe contexts, which
can lead to use-after-free issues.

Instead of calling linux_poll_wakeup() directly use the wake_up()
family of functions in the LinuxKPI to do this.

Bump the FreeBSD version to force recompilation of external kernel modules.

MFC after: 1 week
Sponsored by: Mellanox Technologies