CONFIG_SPL_SYS_[DI]CACHE_OFF: add

While converting CONFIG_SYS_[DI]CACHE_OFF to Kconfig, there are instances
where these configuration items are conditional on SPL. This commit adds SPL
variants of these configuration items, uses CONFIG_IS_ENABLED(), and updates
the configurations as required.

Acked-by: Alexey Brodkin <abrodkin@synopsys.com>
Signed-off-by: Trevor Woerner <trevor@toganlabs.com>
[trini: Make the default depend on the setting for full U-Boot, update
more zynq hardware]
Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/axm_defconfig b/configs/axm_defconfig
index bcc5a0a..73febdf 100644
--- a/configs/axm_defconfig
+++ b/configs/axm_defconfig
@@ -1,4 +1,5 @@
 CONFIG_ARM=y
+CONFIG_SPL_SYS_DCACHE_OFF=y
 CONFIG_SYS_THUMB_BUILD=y
 # CONFIG_SPL_USE_ARCH_MEMCPY is not set
 # CONFIG_SPL_USE_ARCH_MEMSET is not set