spi: fsl_qspi: Build driver only if DM_SPI is available

The driver depends on DM_SPI and if it's not available (e. g. in SPL),
then we should not try to build it as this will fail.

Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index f70851e..216e72c 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -11,6 +11,7 @@
 obj-$(CONFIG_SOFT_SPI) += soft_spi.o
 obj-$(CONFIG_SPI_MEM) += spi-mem.o
 obj-$(CONFIG_TI_QSPI) += ti_qspi.o
+obj-$(CONFIG_FSL_QSPI) += fsl_qspi.o
 else
 obj-y += spi.o
 obj-$(CONFIG_SPI_MEM) += spi-mem-nodm.o
@@ -30,7 +31,6 @@
 obj-$(CONFIG_EXYNOS_SPI) += exynos_spi.o
 obj-$(CONFIG_FSL_DSPI) += fsl_dspi.o
 obj-$(CONFIG_FSL_ESPI) += fsl_espi.o
-obj-$(CONFIG_FSL_QSPI) += fsl_qspi.o
 obj-$(CONFIG_SYNQUACER_SPI) += spi-synquacer.o
 obj-$(CONFIG_ICH_SPI) +=  ich.o
 obj-$(CONFIG_KIRKWOOD_SPI) += kirkwood_spi.o