fix: revert comment which disabled initialization

[valcarcexyz]

Original SWL2001 did not have this initialization commented out:

#if defined( SX128X )
ralf_t modem_radio = RALF_SX128X_INSTANTIATE( NULL );
#elif defined( SX126X )
ralf_t modem_radio = RALF_SX126X_INSTANTIATE( NULL );
#elif defined( LR11XX )
ralf_t modem_radio = RALF_LR11XX_INSTANTIATE( NULL );
#elif defined( LR20XX )
ralf_t modem_radio = RALF_LR20XX_INSTANTIATE( NULL );
#elif defined( SX127X )
#include "sx127x.h"
static sx127x_t sx127x;
ralf_t          modem_radio = RALF_SX127X_INSTANTIATE( &sx127x );
#else
#error "Please select radio board.."
#endif

High relationship with this issue in the zephyr Lora-net/usp_zephyr#2