rockchip: rk3399: Remove dram dfs optimization

This removes an optimization to not recalculate parameters if the
frequency index being switched to hold the next frequency. This is
because some registers do not have a copy per frequency index, so this
optimization might be causing problems.
Signed-off-by: Derek Basehore <dbasehore@chromium.org>

plat/rockchip/rk3399/drivers/dram/dfs.c

@@ -1980,8 +1980,6 @@ static uint32_t prepare_ddr_timing(uint32_t mhz)
 		gen_rk3399_set_odt(1);
 
 	index = (rk3399_dram_status.current_index + 1) & 0x1;
-	if (rk3399_dram_status.index_freq[index] == mhz)
-		return index;
 
 	/*
 	 * checking if having available gate traiing timing for