staging: pi433: rf69.c style fix - code indent should use tabs

This patch fixes the following checkpatch.pl error:

ERROR: code indent should use tabs where possible

in rf69.c file as requested by TODO file.

Additionally some style warnings remain valid here and could be fixed by
another patch.
Signed-off-by: Marcin Ciupak <marcin.s.ciupak@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/pi433/rf69.c

@@ -959,8 +959,8 @@ int rf69_read_fifo (struct spi_device *spi, u8 *buffer, unsigned int size)
 	/* prepare a bidirectional transfer */
 	local_buffer[0] = REG_FIFO;
 	memset(&transfer, 0, sizeof(transfer));
-  	transfer.tx_buf = local_buffer;
-  	transfer.rx_buf = local_buffer;
+	transfer.tx_buf = local_buffer;
+	transfer.rx_buf = local_buffer;
 	transfer.len	= size+1;
 
 	retval = spi_sync_transfer(spi, &transfer, 1);