rockchip: rk3328: enable DMA for MMCs at Rock64

DMA for MMCs can be enabled, since the previous patch fixes
the following issue in SPL:

    Trying to boot from MMC1
    spl: mmc init failed with error: -110
    SPL: failed to boot from all boot devices
    ### ERROR ### Please RESET the board ###

Signed-off-by: Matwey V. Kornilov <matwey.kornilov@gmail.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/arch/arm/dts/rk3328-rock64-u-boot.dtsi b/arch/arm/dts/rk3328-rock64-u-boot.dtsi
index b077436..928911f 100644
--- a/arch/arm/dts/rk3328-rock64-u-boot.dtsi
+++ b/arch/arm/dts/rk3328-rock64-u-boot.dtsi
@@ -25,10 +25,8 @@
 
 &emmc {
 	u-boot,dm-pre-reloc;
-	fifo-mode;
 };
 
 &sdmmc {
 	u-boot,dm-pre-reloc;
-	fifo-mode;
 };