ARM: rmobile: Enable cache command on V3M Eagle

Turning the cache off can help when experimenting with bare metal
applications, enable the cache command on V3M Eagle to make that
easier.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
diff --git a/configs/r8a77970_eagle_defconfig b/configs/r8a77970_eagle_defconfig
index e656377..11f56af 100644
--- a/configs/r8a77970_eagle_defconfig
+++ b/configs/r8a77970_eagle_defconfig
@@ -24,6 +24,7 @@
 CONFIG_CMD_DHCP=y
 CONFIG_CMD_MII=y
 CONFIG_CMD_PING=y
+CONFIG_CMD_CACHE=y
 CONFIG_CMD_EXT2=y
 CONFIG_CMD_EXT4=y
 CONFIG_CMD_EXT4_WRITE=y