i40e: Remove unreachable code

The code at the end of i40e_read_phy_register_clause22() contained
unreachable code and redundant control statements.

This change removes the unreachable code. And deletes the redundant
goto statement and if statement.

Change-ID: I713032b1585396f40f903cbcfdea987abd874400
Signed-off-by: Henry Tieman <henry.w.tieman@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>