misc: eeprom: at24: fix NVMEM name with custom AT24 device name

When the "label" property is set on the AT24 EEPROM the NVMEM devid is
set to NVMEM_DEVID_NONE, but it is not effective since there is a
leftover line setting it back to NVMEM_DEVID_AUTO a few lines after.

Fixes: 61f764c3

 ("eeprom: at24: Support custom device names for AT24 EEPROMs")
Signed-off-by: Diego Santa Cruz <Diego.SantaCruz@spinetix.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>