ARM: shmobile: r8a7779 dtsi: Update unit-addresses for clocks

  - Correct the unit-address for the "cpg_clocks" node,
  - Add missing unit-addresses for the "mstp*_clks" nodes,
  - Rename "cpg_clocks" and "mstp*_clks" nodes to the more generic
    "clocks".

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>