k210: dts: Set PLL1 to the same rate as PLL0

Linux has had some stability issues when using AISRAM with a different
frequency from SRAM. Mirror their change here now that we relocate into
AISRAM.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>