cpu/sam21_common: remove unused defines

cpu/sam21_common/include/periph_cpu_common.h

@@ -115,24 +115,6 @@ typedef enum {
     SPI_PAD_0_SCK_3 = 3,    /**< select pad 0, SCK pad3, only SPI */
 } sercom_spi_txpad_t;
 
-/**
- * @brief   Possible selections for SERCOM SPI data size (inspired by Arduino)
- */
-typedef enum
-{
-    SPI_CHAR_SIZE_8_BITS = 0x0ul,
-    SPI_CHAR_SIZE_9_BITS = 0x1ul,
-} sercom_spi_charsize_t;
-
-/**
- * @brief   Possible selections for SERCOM data (bit) order (inspired by Arduino)
- */
-typedef enum
-{
-    MSB_FIRST = 0,
-    LSB_FIRST = 1,
-} sercom_data_order_t;
-
 /**
  * @brief   Possible selections for SERCOM SPI clock mode (inspired by Arduino)
  */