ice: check the return of ice_ptp_gettimex64

Clang static analysis reports this issue
time64.h:69:50: warning: The left operand of '+'
  is a garbage value
  set_normalized_timespec64(&ts_delta, lhs.tv_sec + rhs.tv_sec,
                                       ~~~~~~~~~~ ^
In ice_ptp_adjtime_nonatomic(), the timespec64 variable 'now'
is set by ice_ptp_gettimex64().  This function can fail
with -EBUSY, so 'now' can have a gargbage value.
So check the return.

Fixes: 06c16d89 ("ice: register 1588 PTP clock device object for E810 devices")
Signed-off-by: Tom Rix <trix@redhat.com>
Tested-by: Gurucharan G <gurucharanx.g@intel.com> (A Contingent worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

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

@@ -1533,9 +1533,12 @@ ice_ptp_settime64(struct ptp_clock_info *info, const struct timespec64 *ts)
 static int ice_ptp_adjtime_nonatomic(struct ptp_clock_info *info, s64 delta)
 {
 	struct timespec64 now, then;
+	int ret;
 
 	then = ns_to_timespec64(delta);
-	ice_ptp_gettimex64(info, &now, NULL);
+	ret = ice_ptp_gettimex64(info, &now, NULL);
+	if (ret)
+		return ret;
 	now = timespec64_add(now, then);
 
 	return ice_ptp_settime64(info, (const struct timespec64 *)&now);