ice: remove unnecessary NULL checks before ptp_read_system_*

The ptp_read_system_prets and ptp_read_system_postts functions already
check for the NULL value of the ptp_system_timestamp structure pointer.
There is no need to check this manually in the ice driver code. Remove
the checks.
Reported-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

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

@@ -219,13 +219,11 @@ ice_ptp_read_src_clk_reg(struct ice_pf *pf, struct ptp_system_timestamp *sts)
 
 	tmr_idx = ice_get_ptp_src_clock_index(hw);
 	/* Read the system timestamp pre PHC read */
-	if (sts)
 	ptp_read_system_prets(sts);
 
 	lo = rd32(hw, GLTSYN_TIME_L(tmr_idx));
 
 	/* Read the system timestamp post PHC read */
-	if (sts)
 	ptp_read_system_postts(sts);
 
 	hi = rd32(hw, GLTSYN_TIME_H(tmr_idx));
@@ -235,10 +233,8 @@ ice_ptp_read_src_clk_reg(struct ice_pf *pf, struct ptp_system_timestamp *sts)
 		/* if TIME_L rolled over read TIME_L again and update
 		 * system timestamps
 		 */
-		if (sts)
 		ptp_read_system_prets(sts);
 		lo = rd32(hw, GLTSYN_TIME_L(tmr_idx));
-		if (sts)
 		ptp_read_system_postts(sts);
 		hi = rd32(hw, GLTSYN_TIME_H(tmr_idx));
 	}