broadcom: tg3: fix use of SPEED_UNKNOWN ethtool constant

tg3 driver uses u16 to store SPEED_UKNOWN ethtool constant,
which is defined as -1, resulting in value truncation and
thus incorrect test results against SPEED_UNKNOWN.

For example, the following test will print "False":

	u16 speed = SPEED_UNKNOWN;

	if (speed == SPEED_UNKNOWN)
	    printf("True");
	else
	    printf("False");

Change storage of speed to use u32 to avoid this issue.
Signed-off-by: Michael Zhivich <mzhivich@akamai.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/tg3.c

@@ -4283,7 +4283,7 @@ static void tg3_power_down(struct tg3 *tp)
 	pci_set_power_state(tp->pdev, PCI_D3hot);
 }
 
-static void tg3_aux_stat_to_speed_duplex(struct tg3 *tp, u32 val, u16 *speed, u8 *duplex)
+static void tg3_aux_stat_to_speed_duplex(struct tg3 *tp, u32 val, u32 *speed, u8 *duplex)
 {
 	switch (val & MII_TG3_AUX_STAT_SPDMASK) {
 	case MII_TG3_AUX_STAT_10HALF:
@@ -4787,7 +4787,7 @@ static int tg3_setup_copper_phy(struct tg3 *tp, bool force_reset)
 	bool current_link_up;
 	u32 bmsr, val;
 	u32 lcl_adv, rmt_adv;
-	u16 current_speed;
+	u32 current_speed;
 	u8 current_duplex;
 	int i, err;
 
@@ -5719,7 +5719,7 @@ static bool tg3_setup_fiber_by_hand(struct tg3 *tp, u32 mac_status)
 static int tg3_setup_fiber_phy(struct tg3 *tp, bool force_reset)
 {
 	u32 orig_pause_cfg;
-	u16 orig_active_speed;
+	u32 orig_active_speed;
 	u8 orig_active_duplex;
 	u32 mac_status;
 	bool current_link_up;
@@ -5823,7 +5823,7 @@ static int tg3_setup_fiber_mii_phy(struct tg3 *tp, bool force_reset)
 {
 	int err = 0;
 	u32 bmsr, bmcr;
-	u16 current_speed = SPEED_UNKNOWN;
+	u32 current_speed = SPEED_UNKNOWN;
 	u8 current_duplex = DUPLEX_UNKNOWN;
 	bool current_link_up = false;
 	u32 local_adv, remote_adv, sgsr;

drivers/net/ethernet/broadcom/tg3.h

@@ -2873,7 +2873,7 @@ struct tg3_tx_ring_info {
 struct tg3_link_config {
 	/* Describes what we're trying to get. */
 	u32				advertising;
-	u16				speed;
+	u32				speed;
 	u8				duplex;
 	u8				autoneg;
 	u8				flowctrl;
@@ -2882,7 +2882,7 @@ struct tg3_link_config {
 	u8				active_flowctrl;
 
 	u8				active_duplex;
-	u16				active_speed;
+	u32				active_speed;
 	u32				rmt_adv;
 };