Update EEPROM block

This addition fixes a random issue that I've encountered where, for some reason, the eeprom is not correctly initialized/addressed. The original code worked fine after the merge of the bank size fix but a random recompilatin brought to my attention that the fw wasn't running correctly.
This addition of the backing size seems to have fixed the issue.

keyboards/cipulot/ec_menhir/info.json

@@ -10,7 +10,8 @@
     "eeprom": {
         "driver": "wear_leveling",
         "wear_leveling": {
-            "driver": "embedded_flash"
+            "driver": "embedded_flash",
+            "backing_size": 4096
         }
     },
     "features": {