ixgbe: Allow reduced delays during SFP detection

Reduce the number of retries during PHY detection. This reduces
pauses when no SFP is present. Once an SFP is detected, the normal
retry count will be used.

Signed-off-by: Mark Rustad <mark.d.rustad@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>