spi: Remove useless restrictions

Signed-off-by: Shoukui Zhang <zhangshoukui@xiaomi.com>

drivers/spi/spi_bitbang.c

@@ -35,8 +35,6 @@
 
 #include <nuttx/mutex.h>
 
-#ifdef CONFIG_SPI_BITBANG
-
 /****************************************************************************
  * Pre-processor Definitions
  ****************************************************************************/
@@ -559,4 +557,3 @@ void spi_destroy_bitbang(FAR struct spi_dev_s *dev)
   kmm_free(dev);
 }
 
-#endif /* CONFIG_SPI_BITBANG */

drivers/spi/spi_driver.c

@@ -37,8 +37,6 @@
 #include <nuttx/mutex.h>
 #include <nuttx/spi/spi_transfer.h>
 
-#ifdef CONFIG_SPI_DRIVER
-
 /****************************************************************************
  * Pre-processor Definitions
  ****************************************************************************/
@@ -393,4 +391,3 @@ int spi_register(FAR struct spi_dev_s *spi, int bus)
   return -ENOMEM;
 }
 
-#endif /* CONFIG_SPI_DRIVER */

drivers/spi/spi_transfer.c

@@ -33,8 +33,6 @@
 #include <nuttx/spi/spi.h>
 #include <nuttx/spi/spi_transfer.h>
 
-#ifdef CONFIG_SPI_EXCHANGE
-
 /****************************************************************************
  * Public Functions
  ****************************************************************************/
@@ -143,4 +141,3 @@ int spi_transfer(FAR struct spi_dev_s *spi, FAR struct spi_sequence_s *seq)
   return ret;
 }
 
-#endif /* CONFIG_SPI_EXCHANGE */