i40e/i40evf: always set the CLEARPBA flag when re-enabling interrupts

In the past we changed driver behavior to not clear the PBA when
re-enabling interrupts. This change was motivated by the flawed belief
that clearing the PBA would cause a lost interrupt if a receive
interrupt occurred while interrupts were disabled.

According to empirical testing this isn't the case. Additionally, the
data sheet specifically says that we should set the CLEARPBA bit when
re-enabling interrupts in a polling setup.

This reverts commit 40d72a50

 ("i40e/i40evf: don't lose interrupts")

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>