clk: imx7d: Correct dram pll type

DRAM PLL is a audio/video type PLL, need to correct
it to get correct ops of PLL.

There is a test_div placed before DRAM PLL's gate, so
add this test div clk.

Signed-off-by: Anson Huang <b20788@freescale.com>
Signed-off-by: Irina Tirdea <irina.tirdea@nxp.com>
Signed-off-by: Abel Vesa <abel.vesa@nxp.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>