spi: Migrate CONFIG_MPC8XXX_SPI to Kconfig

Signed-off-by: Tuomas Tynkkynen <tuomas@tuxera.com>
diff --git a/configs/ids8313_defconfig b/configs/ids8313_defconfig
index ccb84e4..ab4493d 100644
--- a/configs/ids8313_defconfig
+++ b/configs/ids8313_defconfig
@@ -34,4 +34,5 @@
 CONFIG_PHYLIB=y
 # CONFIG_PCI is not set
 CONFIG_SYS_NS16550=y
+CONFIG_MPC8XXX_SPI=y
 CONFIG_OF_LIBFDT=y