net: stmmac: dwmac-meson8b: Move the documentation for the TX delay

Move the documentation for the TX delay above the PRG_ETH0_TXDLY_MASK
definition. Future commits will add more registers also with
documentation above their register bit definitions. Move the existing
comment so it will be consistent with the upcoming changes.
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/dwmac-meson8b.c

@@ -33,6 +33,10 @@
 #define PRG_ETH0_CLK_M250_SEL_SHIFT	4
 #define PRG_ETH0_CLK_M250_SEL_MASK	GENMASK(4, 4)
 
+/* TX clock delay in ns = "8ns / 4 * tx_dly_val" (where 8ns are exactly one
+ * cycle of the 125MHz RGMII TX clock):
+ * 0ns = 0x0, 2ns = 0x1, 4ns = 0x2, 6ns = 0x3
+ */
 #define PRG_ETH0_TXDLY_MASK		GENMASK(6, 5)
 
 /* divider for the result of m250_sel */
@@ -248,10 +252,6 @@ static int meson8b_init_prg_eth(struct meson8b_dwmac *dwmac)
 	switch (dwmac->phy_mode) {
 	case PHY_INTERFACE_MODE_RGMII:
 	case PHY_INTERFACE_MODE_RGMII_RXID:
-		/* TX clock delay in ns = "8ns / 4 * tx_dly_val" (where
-		 * 8ns are exactly one cycle of the 125MHz RGMII TX clock):
-		 * 0ns = 0x0, 2ns = 0x1, 4ns = 0x2, 6ns = 0x3
-		 */
 		tx_dly_val = dwmac->tx_delay_ns >> 1;
 		/* fall through */