clk: exynos5420: Remove aclk66_peric from the clock tree description

The "aclk66_peric" clock is a gate clock with a whole bunch of gates
underneath it.  This big gate isn't very useful to include in our
clock tree.  If any of the children need to be turned on then the big
gate will need to be on anyway.  ...and there are plenty of other "big
gates" that aren't described in our clock tree, some of which shut off
collections of clocks that have no relationship in the hierarchy so
are hard to model.

"aclk66_peric" is causing earlyprintk problems since it gets disabled
as part of the boot process, so let's just remove it.

Strangely (and for no good reason) this clock is exported as part of
the common clock bindings.  Remove it since there are no in-kernel
device trees using it and no reason anyone out of tree should refer to
it either.

Signed-off-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Tomasz Figa <t.figa@samsung.com>