spi: spi-mem: Make spi_mem_default_supports_op() static inline

Stub helper spi_mem_default_supports_op() should
be set to static inline

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/include/linux/spi/spi-mem.h b/include/linux/spi/spi-mem.h
index 1941b84..af9ff2f 100644
--- a/include/linux/spi/spi-mem.h
+++ b/include/linux/spi/spi-mem.h
@@ -315,6 +315,7 @@ spi_controller_dma_unmap_mem_op_data(struct spi_controller *ctlr,
 {
 }
 
+static inline
 bool spi_mem_default_supports_op(struct spi_mem *mem,
 				 const struct spi_mem_op *op)
 {