mtd: spi: Use CONFIG_IS_ENABLED to prevent ifdef

Use CONFIG_IS_ENABLED to prevent ifdef in sf_probe.c

Cc: Simon Glass <sjg@chromium.org>
Cc: Vignesh R <vigneshr@ti.com>
Cc: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
diff --git a/drivers/mtd/spi/sf_probe.c b/drivers/mtd/spi/sf_probe.c
index c2e51f9..ee7cbaf 100644
--- a/drivers/mtd/spi/sf_probe.c
+++ b/drivers/mtd/spi/sf_probe.c
@@ -45,9 +45,8 @@
 	if (ret)
 		goto err_read_id;
 
-#if CONFIG_IS_ENABLED(SPI_FLASH_MTD)
-	ret = spi_flash_mtd_register(flash);
-#endif
+	if (CONFIG_IS_ENABLED(SPI_FLASH_MTD))
+		ret = spi_flash_mtd_register(flash);
 
 err_read_id:
 	spi_release_bus(spi);
@@ -84,9 +83,9 @@
 
 void spi_flash_free(struct spi_flash *flash)
 {
-#if CONFIG_IS_ENABLED(SPI_FLASH_MTD)
-	spi_flash_mtd_unregister();
-#endif
+	if (CONFIG_IS_ENABLED(SPI_FLASH_MTD))
+		spi_flash_mtd_unregister();
+
 	spi_free_slave(flash->spi);
 	free(flash);
 }
@@ -153,9 +152,9 @@
 
 static int spi_flash_std_remove(struct udevice *dev)
 {
-#if CONFIG_IS_ENABLED(SPI_FLASH_MTD)
-	spi_flash_mtd_unregister();
-#endif
+	if (CONFIG_IS_ENABLED(SPI_FLASH_MTD))
+		spi_flash_mtd_unregister();
+
 	return 0;
 }