wifi: esp32: simplify DHCP4 auto-negotiation Kconfig

Remove redundant NET_DHCPV4 dependency and add default
behavior.

Signed-off-by: Muhammad Waleed Badar <walid.badar@gmail.com>
diff --git a/drivers/wifi/esp32/Kconfig.esp32 b/drivers/wifi/esp32/Kconfig.esp32
index fdb2784..a46d689 100644
--- a/drivers/wifi/esp32/Kconfig.esp32
+++ b/drivers/wifi/esp32/Kconfig.esp32
@@ -51,7 +51,7 @@
 
 config ESP32_WIFI_STA_AUTO_DHCPV4
 	bool "Automatically starts DHCP4 negotiation"
-	depends on NET_DHCPV4
+	default y if NET_DHCPV4
 	depends on NET_IPV4
 	help
 	  WiFi driver will automatically initiate DHCPV4 negotiation when connected.