spl: Allow cache drivers to be used in SPL

Add an option for building cache drivers in SPL.

Signed-off-by: Ley Foon Tan <ley.foon.tan@intel.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>
diff --git a/common/spl/Kconfig b/common/spl/Kconfig
index c527617..61488da 100644
--- a/common/spl/Kconfig
+++ b/common/spl/Kconfig
@@ -731,6 +731,12 @@
 	  README.ubispl for more info.
 
 if SPL_DM
+config SPL_CACHE
+	depends on CACHE
+	bool "Support cache drivers in SPL"
+	help
+	  Enable support for cache drivers in SPL.
+
 config SPL_DM_SPI
 	bool "Support SPI DM drivers in SPL"
 	help