net: macb: Add separate definition for PPM fraction

The scaled ppm parameter passed to _adjfine() contains a 16 bit
fraction. This just happens to be the same as SUBNSINCR_SIZE now.
Hence define this separately.
Signed-off-by: Harini Katakam <harini.katakam@xilinx.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/cadence/macb.h

@@ -834,6 +834,9 @@ struct gem_tx_ts {
 /* limit RX checksum offload to TCP and UDP packets */
 #define GEM_RX_CSUM_CHECKED_MASK		2
 
+/* Scaled PPM fraction */
+#define PPM_FRACTION	16
+
 /* struct macb_tx_skb - data about an skb which is being transmitted
  * @skb: skb currently being transmitted, only set for the last buffer
  *       of the frame

drivers/net/ethernet/cadence/macb_ptp.c

@@ -135,7 +135,7 @@ static int gem_ptp_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
 	 * (temp / USEC_PER_SEC) + 0.5
 	 */
 	adj += (USEC_PER_SEC >> 1);
-	adj >>= GEM_SUBNSINCR_SIZE; /* remove fractions */
+	adj >>= PPM_FRACTION; /* remove fractions */
 	adj = div_u64(adj, USEC_PER_SEC);
 	adj = neg_adj ? (word - adj) : (word + adj);