clk: renesas: cpg-mssr: fix kerneldoc of cpg_mssr_priv

The struct cpg_mssr_priv missed proper formatting:

    drivers/clk/renesas/renesas-cpg-mssr.c:142: warning:
        cannot understand function prototype: 'struct cpg_mssr_priv '

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20201103162435.13689-7-krzk@kernel.org


Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>