boards/arduino-mega2560: cleanup in periph_conf.h

- remove unused periph configuration
- fixed doxygen

boards/arduino-mega2560/include/periph_conf.h

@@ -24,15 +24,16 @@ extern "C" {
 #endif
 
 /**
- * @name        Clock configuration
+ * @brief   Clock configuration
  * @{
  */
 #define CLOCK_CORECLOCK     (16000000L)
 /** @} */
 
 /**
- * @name        Timer peripheral configuration
+ * @brief   Timer peripheral configuration
- * @brief       The ATmega2560 has 6 timers. Timer0 and Timer2 are 8 Bit Timers,
+ *
+ * The ATmega2560 has 6 timers. Timer0 and Timer2 are 8 Bit Timers,
  * Timer0 has special uses too and therefore we'll avoid using it.
  * Timer5 has special uses with certain Arduino Shields, too.
  * Therefore we'll also avoid using Timer5.
@@ -133,9 +134,10 @@ extern "C" {
 #define TIMER2_COMPA_ISR    TIMER4_COMPA_vect
 #define TIMER2_COMPB_ISR    TIMER4_COMPB_vect
 #define TIMER2_COMPC_ISR    TIMER4_COMPC_vect
+/** @} */
 
 /**
- * @name UART configuration
+ * @brief   UART configuration
  * @{
  */
 #define UART_NUMOF          (4U)
@@ -239,20 +241,7 @@ extern "C" {
 #define UART3_SET_8BIT_SIZE UART3_CTRL_STAT_C |= UART3_8BIT_SIZE
 #define UART3_RECEIVED_DATA (UART3_CTRL_STAT_A & (1 << UART3_RX_COMPLETE))
 #define UART3_DTREG_EMPTY   (UART3_CTRL_STAT_A & (1 << UART3_DATA_EMPTY))
-
+/** @} */
-/**
- * @brief ADC configuration
- */
-#define ADC_NUMOF           (0U)
-#define ADC_0_EN            0
-#define ADC_1_EN            0
-
-/**
- * @brief PWM configuration
- */
-#define PWM_NUMOF           (0U)
-#define PWM_0_EN            0
-#define PWM_1_EN            0
 
 /**
  * @brief SPI configuration
@@ -272,13 +261,6 @@ extern "C" {
 #define SPI_0_EN            1           /* remove once SPI rework is done */
 /** @} */
 
-/**
- * @brief I2C configuration
- */
-#define I2C_NUMOF           (0U)                                                    /* TODO */
-#define I2C_0_EN            0
-#define I2C_0_EN            0
-
 #ifdef __cplusplus
 }
 #endif