devices: vhoost cpu->copy array overflow on tcp jumbo frame (65535 bytes)

devices: vhoost cpu->copy array overflow on tcp jumbo frame (65535 bytes)

We reserve 40 slots in cpu->copy array prior to copy out to avoid overflowing
the array. However, 40 is not enough for the jumbo frame because desceiptor
buffer len is likely at 1536. Change the reserve to 200 and add ASSERT to avoid
encountering the same problem in the future.

Type: fix

Signed-off-by: Steven Luong <sluong@cisco.com>
Change-Id: Ibf0c03c4b4f33e781d5be8679ccd6c3a4b4a646d
(cherry picked from commit 7331005c16d0e1499080899b2a0676a0cd945595)