i40e/i40evf: Remove I40E_MAX_USER_PRIORITY define

This patch removes the duplicate definition of I40E_MAX_USER_PRIORITY
in i40e.h that is not needed.

Signed-off-by: Catherine Sullivan <catherine.sullivan@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>