feat(imx8m): add 3600 MTps DDR PLL rate

Add 3600 MTps DRAM and its 900 MHz PLL setting M=300 P=8 S=0 , so
24 MHz * 300 / 8 / 2^0 = 900 MHz ~ 3600 MTps (x4) .

Signed-off-by: Marek Vasut <marex@denx.de>
Change-Id: If2743827294efc0f981718f04b772cc462846195
1 file changed