staging: pi433: fix CamelCase for DIONumber variable

Fixes checkpatch warning:

  CHECK: Avoid CamelCase: <DIONumber>
Signed-off-by: Valentin Vidic <Valentin.Vidic@CARNet.hr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/pi433/rf69.c

@@ -501,14 +501,14 @@ int rf69_set_ook_threshold_dec(struct spi_device *spi, enum threshold_decrement
 	}
 }
 
-int rf69_set_dio_mapping(struct spi_device *spi, u8 DIONumber, u8 value)
+int rf69_set_dio_mapping(struct spi_device *spi, u8 dio_number, u8 value)
 {
 	u8 mask;
 	u8 shift;
 	u8 dio_addr;
 	u8 dio_value;
 
-	switch (DIONumber) {
+	switch (dio_number) {
 	case 0:
 		mask = MASK_DIO0; shift = SHIFT_DIO0; dio_addr = REG_DIOMAPPING1;
 		break;

drivers/staging/pi433/rf69.h

@@ -41,7 +41,7 @@ int rf69_set_lna_gain(struct spi_device *spi, enum lnaGain lnaGain);
 int rf69_set_bandwidth(struct spi_device *spi, enum mantisse mantisse, u8 exponent);
 int rf69_set_bandwidth_during_afc(struct spi_device *spi, enum mantisse mantisse, u8 exponent);
 int rf69_set_ook_threshold_dec(struct spi_device *spi, enum threshold_decrement threshold_decrement);
-int rf69_set_dio_mapping(struct spi_device *spi, u8 DIONumber, u8 value);
+int rf69_set_dio_mapping(struct spi_device *spi, u8 dio_number, u8 value);
 bool rf69_get_flag(struct spi_device *spi, enum flag flag);
 int rf69_set_rssi_threshold(struct spi_device *spi, u8 threshold);
 int rf69_set_preamble_length(struct spi_device *spi, u16 preamble_length);