From: Jeff Kirsher <redacted>
Date: Tue, 24 Nov 2009 20:51:06 -0800

From: Shannon Nelson <redacted>

The driver was doing a divide by zero when adjusting tx-usecs.
This patch removes the divide by zero code and changes the logic slightly
to ignore tx-usecs in the case of shared TxRx vectors.

Cc: Jesse Brandeburg <redacted>
Signed-off-by: Shannon Nelson <redacted>
Signed-off-by: Jeff Kirsher <redacted>

Applied.