variants: Lilygo T-Echo (Lite): Use DC/DC regulator

The schematic shows the LC circuit for the internal DC/DC regulator
to be available. Enable it to save power.

Signed-off-by: Frieder Schrempf <frieder@fris.de>

variants/lilygo_techo/TechoBoard.h

@@ -13,7 +13,7 @@
 #define PIN_VBAT_READ     (4)
 #define REAL_VBAT_MV_PER_LSB (VBAT_DIVIDER_COMP * VBAT_MV_PER_LSB)
 
-class TechoBoard : public NRF52BoardOTA {
+class TechoBoard : public NRF52BoardDCDC, public NRF52BoardOTA {
 public:
   TechoBoard() : NRF52BoardOTA("TECHO_OTA") {}
   void begin();

variants/lilygo_techo_lite/TechoBoard.h

@@ -13,7 +13,7 @@
 #define PIN_VBAT_READ     (4)
 #define REAL_VBAT_MV_PER_LSB (VBAT_DIVIDER_COMP * VBAT_MV_PER_LSB)
 
-class TechoBoard : public NRF52BoardOTA {
+class TechoBoard : public NRF52BoardDCDC, public NRF52BoardOTA {
 public:
   TechoBoard() : NRF52BoardOTA("TECHO_OTA") {}
   void begin();