ixgbevf: Convert printks to pr_<level>

ixgbevf: Convert printks to pr_<level>

Based on the original patch from Joe Perches <joe@perches.com>

Use the current logging styles, prefix output with "ixgbevf: "

Add #define pr_fmt
Coalesce formats.

-v2 Fix-up to make checkpatch.pl compliant and remove change to
    copyright line

CC: Joe Perches <joe@perches.com>
(cherry picked from commit dbd9636e281895cd3a15682f0966fb545ddff9e8)
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Tested-by: Sibai Li <sibai.li@intel.com>
Signed-off-by: Joe Jin <joe.jin@oracle.com>