Simple Power-Managed bus controller may need functional clock(s)
to be enabled before child devices connected to the bus can be
accessed.  Get the clock(s) as a bulk and enable/disable the
clock(s) when the bus is being power managed.

One example is that Freescale i.MX8qxp pixel link MSI bus controller
needs MSI clock and AHB clock to be enabled before accessing child
devices.
Signed-off-by: Liu Ying <victor.liu@nxp.com>
Tested-by: Maxim Kochetkov <fido_max@inbox.ru>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20221226031417.1056745-1-victor.liu@nxp.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>