rockchip: rk3368: defconfig: remove SPL raw image support

RK3368 SPL only support FIT image for ATF bl31.

Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/configs/evb-px5_defconfig b/configs/evb-px5_defconfig
index 46a42a7..5a06b2a 100644
--- a/configs/evb-px5_defconfig
+++ b/configs/evb-px5_defconfig
@@ -29,6 +29,7 @@
 CONFIG_DISPLAY_BOARDINFO_LATE=y
 CONFIG_ARCH_EARLY_INIT_R=y
 CONFIG_SPL_BOOTROM_SUPPORT=y
+# CONFIG_SPL_RAW_IMAGE_SUPPORT is not set
 CONFIG_TPL_SYS_MALLOC_SIMPLE=y
 CONFIG_SPL_STACK_R=y
 CONFIG_SPL_ATF=y