spi: Move SPI drivers to defconfig

There are already Kconfig options for SPI drivers, but we
have not moved them from config.h to defconfig files. This
commit does this in a batch.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/configs/stv0991_defconfig b/configs/stv0991_defconfig
index 60de787..b859632 100644
--- a/configs/stv0991_defconfig
+++ b/configs/stv0991_defconfig
@@ -13,3 +13,4 @@
 CONFIG_OF_CONTROL=y
 CONFIG_NETDEVICES=y
 CONFIG_ETH_DESIGNWARE=y
+CONFIG_CADENCE_QSPI=y