ice: remove invalid parameter of equalizer

It occurred that in the commit 70838938 ("ice: Implement driver
functionality to dump serdes equalizer values") the invalid DRATE parameter
for reading has been added. The output of the command:

  $ ethtool -d <ethX>

returns the garbage value in the place where DRATE value should be
stored.

Remove mentioned parameter to prevent return of corrupted data to
userspace.

Fixes: 70838938 ("ice: Implement driver functionality to dump serdes equalizer values")
Signed-off-by: Mateusz Polchlopek <mateusz.polchlopek@intel.com>
Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Tested-by: Rinitha S <sx.rinitha@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>