net: macb: Set MDIO clock divisor for pclk higher than 160MHz

Currently macb sets clock divisor for pclk up to 160 MHz.
Function gem_mdc_clk_div was updated to enable divisor
for higher values of pclk.

Signed-off-by: Bartosz Wawrzyniak <bwawrzyn@cisco.com>
Reviewed-by: Michal Kubiak <michal.kubiak@intel.com>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/cadence/macb.h

@@ -692,6 +692,8 @@
 #define GEM_CLK_DIV48				3
 #define GEM_CLK_DIV64				4
 #define GEM_CLK_DIV96				5
+#define GEM_CLK_DIV128				6
+#define GEM_CLK_DIV224				7
 
 /* Constants for MAN register */
 #define MACB_MAN_C22_SOF			1

drivers/net/ethernet/cadence/macb_main.c

@@ -2640,8 +2640,12 @@ static u32 gem_mdc_clk_div(struct macb *bp)
 		config = GEM_BF(CLK, GEM_CLK_DIV48);
 	else if (pclk_hz <= 160000000)
 		config = GEM_BF(CLK, GEM_CLK_DIV64);
-	else
+	else if (pclk_hz <= 240000000)
 		config = GEM_BF(CLK, GEM_CLK_DIV96);
+	else if (pclk_hz <= 320000000)
+		config = GEM_BF(CLK, GEM_CLK_DIV128);
+	else
+		config = GEM_BF(CLK, GEM_CLK_DIV224);
 
 	return config;
 }