staging: mt7621-spi: Use tabs for indentation instead of spaces.

The patch fixes following checkpatch.pl issue:
ERROR : code indent should use tabs where possible
Signed-off-by: Sankalp Negi <sankalpnegi2310@gmail.com>
Reviewed-by: NeilBrown <neil@brown.name>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/mt7621-spi/spi-mt7621.c

@@ -107,7 +107,7 @@ static void mt7621_spi_set_cs(struct spi_device *spi, int enable)
 	int cs = spi->chip_select;
 	u32 polar = 0;
 
-        mt7621_spi_reset(rs, cs);
+	mt7621_spi_reset(rs, cs);
 	if (enable)
 		polar = BIT(cs);
 	mt7621_spi_write(rs, MT7621_SPI_POLAR, polar);