mt76: eeprom: tolerate corrected bit-flips

mtd_read() returns -EUCLEAN in case of corrected bit-flips.
As data was read, don't error out in this case.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Acked-by: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: Felix Fietkau <nbd@nbd.name>