bindesc: fix typo in errno (ENONET->ENOENT)

Fix typo in errno which isn't caught when building since ENONET
is also a valid code, despite not being defined (nor allowed?)
in Zephyr proper.

Signed-off-by: Benjamin Cabé <benjamin@zephyrproject.org>

subsys/bindesc/bindesc_read.c

@@ -118,7 +118,7 @@ int bindesc_open_ram(struct bindesc_handle *handle, const uint8_t *address, size
 
 	if (*(uint64_t *)address != BINDESC_MAGIC) {
 		LOG_ERR("Magic not found in given address");
-		return -ENONET;
+		return -ENOENT;
 	}
 
 	handle->address = address;