On my test environment the throughput of a file transfer drops
from 4.4MBps to 116KBps due the number of repeated warning
messages. This patch removes the warning messages as DMA works
correctly with addresses using 0xC0000000 bits.

Signed-off-by: Peter Senna Tschudin <peter.senna@gmail.com>
Acked-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>