Tsi108_eth: remove not needed code

Code clean-up for tsi108_eth network driver.
This patch removes not needed dummy read and the corresponding comment.
The PHY logic requires two reads from the status register to get
current link status. This is done correctly inside mii_check_media().

Signed-off-by: Alexandre Bounine <alexandreb@tundra.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>