spi: legacy-spi-engine: no offload support as a module

No offload support for builtin users when using the legacy driver as a
module.

Signed-off-by: Jorge Marques <[email protected]>

Author: gastmaier

include/linux/spi/legacy-spi-engine.h

@@ -9,7 +9,7 @@
 #ifndef _INCLUDE_LINUX_SPI_SPI_ENGINE_H_
 #define _INCLUDE_LINUX_SPI_SPI_ENGINE_H_
 
-#ifdef CONFIG_SPI_AXI_SPI_ENGINE
+#if IS_REACHABLE(CONFIG_SPI_AXI_SPI_ENGINE)
 
 bool legacy_spi_engine_offload_supported(struct spi_device *spi);
 void legacy_spi_engine_offload_enable(struct spi_device *spi, bool enable);