PXE: add expected env vars

Signed-off-by: John Rigby <john.rigby@linaro.org>
diff --git a/include/configs/omap4_panda.h b/include/configs/omap4_panda.h
index d3063f4..d23325d 100644
--- a/include/configs/omap4_panda.h
+++ b/include/configs/omap4_panda.h
@@ -175,6 +175,8 @@
 #define CONFIG_EXTRA_ENV_SETTINGS \
 	"loadaddr=0x82000000\0" \
 	"pxecfg_ram=0x88000000\0" \
+	"kernel_ram=0x80200000\0" \
+	"initrd_ram=0x81600000\0" \
 	"console=ttyS2,115200n8\0" \
 	"usbtty=cdc_acm\0" \
 	"vram=16M\0" \