ice: fix PHY timestamp extraction for ETH56G

Fix incorrect PHY timestamp extraction for ETH56G.
It's better to use FIELD_PREP() than manual shift.

Fixes: 7cab44f ("ice: Introduce ETH56G PHY model for E825C products")
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Przemyslaw Korba <przemyslaw.korba@intel.com>
Tested-by: Pucha Himasekhar Reddy <himasekharx.reddy.pucha@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

Author: Przekorb

drivers/net/ethernet/intel/ice/ice_ptp_hw.c

@@ -1518,7 +1518,8 @@ static int ice_read_ptp_tstamp_eth56g(struct ice_hw *hw, u8 port, u8 idx,
 	 * lower 8 bits in the low register, and the upper 32 bits in the high
 	 * register.
 	 */
-	*tstamp = ((u64)hi) << TS_PHY_HIGH_S | ((u64)lo & TS_PHY_LOW_M);
+	*tstamp = FIELD_PREP(TS_PHY_HIGH_M, hi) |
+		  FIELD_PREP(TS_PHY_LOW_M, lo);
 
 	return 0;
 }

drivers/net/ethernet/intel/ice/ice_ptp_hw.h

@@ -682,9 +682,8 @@ static inline bool ice_is_dual(struct ice_hw *hw)
 #define TS_HIGH_M			0xFF
 #define TS_HIGH_S			32
 
-#define TS_PHY_LOW_M			0xFF
-#define TS_PHY_HIGH_M			0xFFFFFFFF
-#define TS_PHY_HIGH_S			8
+#define TS_PHY_LOW_M			GENMASK(7, 0)
+#define TS_PHY_HIGH_M			GENMASK_ULL(39, 8)
 
 #define BYTES_PER_IDX_ADDR_L_U		8
 #define BYTES_PER_IDX_ADDR_L		4