net: dsa: microchip: Fix ksz_read64()

[ Upstream commit c34f674 ]

ksz_read64() currently does some dubious byte-swapping on the two
halves of a 64-bit register, and then only returns the high bits.
Replace this with a straightforward expression.

Fixes: e66f840 ("net: dsa: ksz: Add Microchip KSZ8795 DSA driver")
Signed-off-by: Ben Hutchings <ben.hutchings@mind.be>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/net/dsa/microchip/ksz_common.h

@@ -210,12 +210,8 @@ static inline int ksz_read64(struct ksz_device *dev, u32 reg, u64 *val)
 	int ret;
 
 	ret = regmap_bulk_read(dev->regmap[2], reg, value, 2);
-	if (!ret) {
-		/* Ick! ToDo: Add 64bit R/W to regmap on 32bit systems */
-		value[0] = swab32(value[0]);
-		value[1] = swab32(value[1]);
-		*val = swab64((u64)*value);
-	}
+	if (!ret)
+		*val = (u64)value[0] << 32 | value[1];
 
 	return ret;
 }