mtd: Drop unused CONFIG_S32V234

This option does not exist, so the Makefile rule does nothing. Drop it.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/cpu/armv8/Makefile b/arch/arm/cpu/armv8/Makefile
index 2e4bf9e..bba4f57 100644
--- a/arch/arm/cpu/armv8/Makefile
+++ b/arch/arm/cpu/armv8/Makefile
@@ -39,7 +39,6 @@
 endif
 
 obj-$(CONFIG_FSL_LAYERSCAPE) += fsl-layerscape/
-obj-$(CONFIG_S32V234) += s32v234/
 obj-$(CONFIG_TARGET_HIKEY) += hisilicon/
 obj-$(CONFIG_ARMV8_PSCI) += psci.o
 obj-$(CONFIG_TARGET_BCMNS3) += bcmns3/