spi/bitbang: Unexport spi_bitbang_transfer()

Currently no drivers use the ability to override spi_bitbang_transfer()
and if any started this would make it harder to convert the bitbang code
to use transfer_one_message() so remove the export in order to prevent
anyone starting.
Signed-off-by: Mark Brown <broonie@linaro.org>

drivers/spi/spi-bitbang.c

@@ -376,7 +376,7 @@ static void bitbang_work(struct work_struct *work)
 /**
  * spi_bitbang_transfer - default submit to transfer queue
  */
-int spi_bitbang_transfer(struct spi_device *spi, struct spi_message *m)
+static int spi_bitbang_transfer(struct spi_device *spi, struct spi_message *m)
 {
 	struct spi_bitbang	*bitbang;
 	unsigned long		flags;
@@ -398,7 +398,6 @@ int spi_bitbang_transfer(struct spi_device *spi, struct spi_message *m)
 
 	return status;
 }
-EXPORT_SYMBOL_GPL(spi_bitbang_transfer);
 
 /*----------------------------------------------------------------------*/
 

include/linux/spi/spi_bitbang.h

@@ -41,7 +41,6 @@ struct spi_bitbang {
  */
 extern int spi_bitbang_setup(struct spi_device *spi);
 extern void spi_bitbang_cleanup(struct spi_device *spi);
-extern int spi_bitbang_transfer(struct spi_device *spi, struct spi_message *m);
 extern int spi_bitbang_setup_transfer(struct spi_device *spi,
 				      struct spi_transfer *t);