ice: update ethtool stats on-demand

Users expect ethtool statistics to be updated on-demand when invoking
'ethtool -S <iface>' instead of providing a snapshot of statistics taken
once a second (the frequency of the watchdog task where stats are currently
updated).  Update stats every time 'ethtool -S <iface>' is run.

Also, fix an indentation style issue and an unnecessary local variable
initialization in ice_get_ethtool_stats() discovered while investigating
the subject issue.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>