spl: cache: Allow cache drivers in SPL

When ax25-ae350 try to enable v5l2 cache
driver in SPL configuration, it need this
option for cache support in SPL.

Signed-off-by: Rick Chen <rick@andestech.com>
Cc: KC Lin <kclin@andestech.com>
Cc: Alan Kao <alankao@andestech.com>
diff --git a/common/spl/Kconfig b/common/spl/Kconfig
index c8cb715..a724127 100644
--- a/common/spl/Kconfig
+++ b/common/spl/Kconfig
@@ -439,6 +439,13 @@
 	  ensure this information is available to the next image
 	  invoked).
 
+config SPL_CACHE_SUPPORT
+	bool "Support CACHE drivers"
+	help
+	  Enable CACHE drivers in SPL. These drivers can keep data so that
+	  future requests for that data can be served faster. Enable this option
+	  to build the drivers in drivers/cache as part of an SPL build.
+
 config SPL_CPU_SUPPORT
 	bool "Support CPU drivers"
 	help