ice: correct PTP register access debug messages

Report a write failure rather than a read failure when updating
PHY_VENDOR_TXLANE_THRESH.

Fix newline placement in PHY register read and threshold write failure
messages. No functional changes.

Signed-off-by: Alok Tiwari <alok.a.tiwari@oracle.com>
Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>