tcp: Try harder to restore recv queue

On restore we try to put data back into recv queue with quite
big chunks. However the kernel doesn't try hard to split the
data into packets in repair mode for this queue and just
allocates the linear skb of the given size. If the size is
moderately big, the allocation is subject to fail, slab doesn't
reliably allocates memory over 4k.

So, when failing with big chunk on recv queue -- shrink the
chunk and try again.

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Acked-by: Andrew Vagin <avagin@virtuozzo.com>