net: dsa: mt7530: use p5_interface_select as data type for p5_intf_sel

Use the p5_interface_select enumeration as the data type for the
p5_intf_sel field. This ensures p5_intf_sel can only take the values
defined in the p5_interface_select enumeration.

Remove the explicit assignment of 0 to P5_DISABLED as the first enum item
is automatically assigned 0.
Signed-off-by: Arınç ÜNAL <arinc.unal@arinc9.com>
Acked-by: Daniel Golle <daniel@makrotopia.org>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20240122-for-netnext-mt7530-improvements-1-v3-2-042401f2b279@arinc9.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/dsa/mt7530.h

@@ -683,7 +683,7 @@ struct mt7530_port {
 
 /* Port 5 interface select definitions */
 enum p5_interface_select {
-	P5_DISABLED = 0,
+	P5_DISABLED,
 	P5_INTF_SEL_PHY_P0,
 	P5_INTF_SEL_PHY_P4,
 	P5_INTF_SEL_GMAC5,
@@ -776,7 +776,7 @@ struct mt7530_priv {
 	bool			mcm;
 	phy_interface_t		p6_interface;
 	phy_interface_t		p5_interface;
-	unsigned int		p5_intf_sel;
+	enum p5_interface_select p5_intf_sel;
 	u8			mirror_rx;
 	u8			mirror_tx;
 	struct mt7530_port	ports[MT7530_NUM_PORTS];