ice: Change minimum descriptor count value for Tx/Rx rings

Change minimum number of descriptor count from 32 to 64. This is to have
a feature parity with previous Intel NIC drivers.

Signed-off-by: Preethi Banala <preethi.banala@intel.com>
Signed-off-by: Anirudh Venkataramanan <anirudh.venkataramanan@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>