Linux: Pass size argument of epoll_create to the kernel

The kernel actually verifies it, and a garbage value in the register
causes improper system call failures.

Fixes commit c1c0dea3 ("Linux: Remove epoll_create,
inotify_init from syscalls.list") and commit d1d23b13
("Lninux: consolidate epoll_create implementation").

Reviewed-by: Carlos O'Donell <carlos@redhat.com>