igb: Fix for issue where values could be too high for udelay function.

This patch changes the igb_phy_has_link function to check the value of the
parameter before deciding to use udelay or mdelay in order to be sure that
the value is not too high for udelay function.

CC: stable kernel <stable@vger.kernel.org> # 3.9+
Signed-off-by: Sunil K Pandey <sunil.k.pandey@intel.com>
Signed-off-by: Kevin B Smith <kevin.b.smith@intel.com>
Signed-off-by: Carolyn Wyborny <carolyn.wyborny@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>