net: stmmac: dwmac-stm32: Fix Mhz to MHz

Trivial, fix up the comments using 'Mhz' to 'MHz'.
No functional change.
Signed-off-by: Marek Vasut <marex@denx.de>
Signed-off-by: Christophe Roullier <christophe.roullier@foss.st.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

drivers/net/ethernet/stmicro/stmmac/dwmac-stm32.c

@@ -58,7 +58,7 @@
  * Below table summarizes the clock requirement and clock sources for
  * supported phy interface modes.
  * __________________________________________________________________________
- *|PHY_MODE | Normal | PHY wo crystal|   PHY wo crystal   |No 125Mhz from PHY|
+ *|PHY_MODE | Normal | PHY wo crystal|   PHY wo crystal   |No 125MHz from PHY|
  *|         |        |      25MHz    |        50MHz       |                  |
  * ---------------------------------------------------------------------------
  *|  MII    |	 -   |     eth-ck    |	      n/a	  |	  n/a        |
@@ -367,7 +367,7 @@ static int stm32mp1_parse_data(struct stm32_dwmac *dwmac,
 	/* Gigabit Ethernet 125MHz clock selection. */
 	dwmac->eth_clk_sel_reg = of_property_read_bool(np, "st,eth-clk-sel");
 
-	/* Ethernet 50Mhz RMII clock selection */
+	/* Ethernet 50MHz RMII clock selection */
 	dwmac->eth_ref_clk_sel_reg =
 		of_property_read_bool(np, "st,eth-ref-clk-sel");