i40e: Fix inconsistent use of PF/VF vs pf/vf

Joe Perches pointed out that we were inconsistent in the use of
PF vs pf or VF vs vf in our driver code.  Since acronyms are usually
capitalized to denote that it is an acronym, changed all references to
be consistent throughout the code.

Reported-by: Joe Perches <joe@perches.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
index 6beab94..9b11f2e 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
@@ -45,7 +45,7 @@
  * i40e_program_fdir_filter - Program a Flow Director filter
  * @fdir_data: Packet data that will be filter parameters
  * @raw_packet: the pre-allocated packet buffer for FDir
- * @pf: The pf pointer
+ * @pf: The PF pointer
  * @add: True for add/update, False for remove
  **/
 int i40e_program_fdir_filter(struct i40e_fdir_filter *fdir_data, u8 *raw_packet,