devices: virtio: wl: Stop using non-blocking sockets
devices: virtio: wl: Stop using non-blocking sockets

Non-blocking sockets require proper EAGAIN handling in crosvm and the
guest kernel.
Without it, guest writing data faster than host reading results in the
guest kernel returning ENODEV.

Use blocking sockets to avoid this problem, and to be consistent with
pipes which are blocking in wl.rs.

BUG=b:153858766
TEST=Launch ARCVM

Change-Id: If795ee0035dc057de0e155470e231d41f30d3a0e
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/2148985
Tested-by: Ryo Hashimoto <7ea00519fdb4bf6e413a65300cdb4cc81913fc76@chromium.org>
Tested-by: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>
Reviewed-by: Zach Reizner <3374927928a53d04457674c546bd4de57c2044ec@chromium.org>
Commit-Queue: Ryo Hashimoto <7ea00519fdb4bf6e413a65300cdb4cc81913fc76@chromium.org>

google/crosvm,google/crosvm,google/crosvm,google/crosvm