clk: imx7d: only enable minimum required clocks

Formerly clk core does not support imx7d clock type well that all
its clock operations requires the parent clock on.
Therefore we enabled all clocks by default in clock driver
initialization for other module clocks operate well.

After patch 'clk: imx7d: using api with flag CLK_OPS_PARENT_ENABLE',
clk core can handle such clock type well, so we don't have to enable
them all by default anymore. Instead, we only enable a minimum required
set of clocks.

Cc: Michael Turquette <mturquette@baylibre.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>