drv: downgrade EEPROM not found from error to warning

Even though having a working EEPROM is part of the FMC standard, it is not
strictly needed for a driver to work. Or at least, it is not needed by the FMC
framework to continue the loading process.

Hence, we forgive the lack of an EEPROM and move on. If a driver wants to read
data from the EEPROM, it will then need to fail later.

Signed-off-by: Federico Vaga <federico.vaga@cern.ch>

drivers/fmc/fmc-eeprom.c

@@ -194,10 +194,9 @@ static int __fmc_slot_eeprom_add(struct fmc_slot *slot,
 	kfree(nvmem_parent_name);
 
 	if (IS_ERR_OR_NULL(slot->nvmem)) {
-		int err = PTR_ERR(slot->nvmem);
 		slot->nvmem = NULL;
-		dev_err(&slot->dev, "Can't find attached EEPROM (%d)\n", err);
-		return err;
+		dev_warn(&slot->dev, "Can't find attached EEPROM (%ld)\n",
+			 PTR_ERR(slot->nvmem));
 	}
 #endif