ixgbe: consolidate all setting of MRQC into one function

This change simplifies the configuration of MRQC by consolidating the
setting of it into one function. As such the register is no longer set in
multiple places which should make any future changes easier to work with.
In addition we can combine RSS related register writes into the call since
enabling all of those bits without enabling RSS itself in MRQC should have
no effect.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>