usb-net/pegasus: fix pegasus carrier detection

Broken by 4a1728a28a193aa388900714bbb1f375e08a6d8e which switched the
return semantics of read_mii_word() but didn't fix usage of
read_mii_word() to conform to the new semantics.

Setting carrier to off based on the NO_CARRIER flag is also incorrect as
that flag only triggers on TX failure and therefore isn't correct when
no frames are being transmitted.  Since there is already a 2*HZ MII
carrier check going on, defer to that.

Add a TRUST_LINK_STATUS feature flag for adapters where the LINK_STATUS
flag is actually correct, and use that rather than the NO_CARRIER flag.

Signed-off-by: Dan Williams <dcbw@redhat.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/usb/net/pegasus.h b/drivers/usb/net/pegasus.h
index c746782..c7aadb4 100644
--- a/drivers/usb/net/pegasus.h
+++ b/drivers/usb/net/pegasus.h
@@ -11,6 +11,7 @@
 
 #define	PEGASUS_II		0x80000000
 #define	HAS_HOME_PNA		0x40000000
+#define	TRUST_LINK_STATUS	0x20000000
 
 #define	PEGASUS_MTU		1536
 #define	RX_SKBS			4
@@ -203,7 +204,7 @@
 PEGASUS_DEV( "Allied Telesyn Int. AT-USB100", VENDOR_ALLIEDTEL, 0xb100,
 		DEFAULT_GPIO_RESET | PEGASUS_II )
 PEGASUS_DEV( "Belkin F5D5050 USB Ethernet", VENDOR_BELKIN, 0x0121,
-		DEFAULT_GPIO_RESET | PEGASUS_II )
+		DEFAULT_GPIO_RESET | PEGASUS_II | TRUST_LINK_STATUS )
 PEGASUS_DEV( "Billionton USB-100", VENDOR_BILLIONTON, 0x0986,
 		DEFAULT_GPIO_RESET )
 PEGASUS_DEV( "Billionton USBLP-100", VENDOR_BILLIONTON, 0x0987,