clk: hi6220: use CLK_OF_DECLARE_DRIVER for sysctrl and mediactrl clock init

The hi6220-sysctrl and hi6220-mediactrl are not only clock provider but
also reset controller.  It worked fine that single sysctrl/mediactrl
device node in DT can be used to initialize clock driver and populate
platform device for reset controller.  But it stops working after
commit 989eafd0

 ("clk: core: Avoid double initialization of clocks")
gets merged.  The commit sets flag OF_POPULATED during clock
initialization to skip the platform device populating for the same
device node.  On hi6220, it effectively makes hi6220-sysctrl reset
driver not probe any more.

The patch changes hi6220 sysctrl and mediactrl clock init macro from
CLK_OF_DECLARE to CLK_OF_DECLARE_DRIVER, so that the reset driver using
the same hardware block can continue working.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Tested-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>