hyperv: Increase the buffer length for netvsc_channel_cb()

When the buffer is too small for a packet from VMBus, a bigger buffer will be
allocated in netvsc_channel_cb() and retry reading the packet from VMBus.
Increasing this buffer size will reduce the retry overhead.

Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Reviewed-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --cc drivers/net/hyperv/hyperv_net.h
Simple merge

diff --cc drivers/net/hyperv/netvsc.c
Simple merge