e1000e: Correct NVM checksum verification flow

Update MAC type check e1000_pch_tgp because for e1000_pch_cnp,
NVM checksum update is still possible.
Emit a more detailed warning message.

Bugzilla: https://bugzilla.opensuse.org/show_bug.cgi?id=1191663
Fixes: 4051f683 ("e1000e: Do not take care about recovery NVM checksum")
Reported-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
Signed-off-by: Sasha Neftin <sasha.neftin@intel.com>
Tested-by: Naama Meir <naamax.meir@linux.intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

drivers/net/ethernet/intel/e1000e/ich8lan.c

@@ -4140,9 +4140,9 @@ static s32 e1000_validate_nvm_checksum_ich8lan(struct e1000_hw *hw)
 		return ret_val;
 
 	if (!(data & valid_csum_mask)) {
-		e_dbg("NVM Checksum Invalid\n");
+		e_dbg("NVM Checksum valid bit not set\n");
 
-		if (hw->mac.type < e1000_pch_cnp) {
+		if (hw->mac.type < e1000_pch_tgp) {
 			data |= valid_csum_mask;
 			ret_val = e1000_write_nvm(hw, word, 1, &data);
 			if (ret_val)