FR2: GPIO configuration for Interdigital Radio Unit

For FR2 and including analog beamforming, we control the beams via GPIO
on radio units.

In this commit, introduce a configuration option to switch the GPIO
control for different devices: "generic" is the current GPIO control,
"interdigital" configures the GPIO configuration to be used with an
InterDigital device.

radio/COMMON/common_lib.h

@@ -173,6 +173,10 @@ typedef struct {
   notifiedFIFO_t *resp;
 } udp_ctx_t;
 
+typedef enum {
+  RU_GPIO_CONTROL_GENERIC,
+  RU_GPIO_CONTROL_INTERDIGITAL,
+} gpio_control_t;
 
 /*! \brief RF frontend parameters set by application */
 typedef struct {
@@ -275,6 +279,8 @@ typedef struct {
   int rxfh_cores[4];
   //! Core IDs for TX FH
   int txfh_cores[4];
+  //! select the GPIO control method
+  gpio_control_t gpio_controller;
 } openair0_config_t;
 
 /*! \brief RF mapping */