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

drivers/clk/renesas/renesas-cpg-mssr.c

@@ -119,7 +119,8 @@ static const u16 srstclr_for_v3u[] = {
 };
 
 /**
- * Clock Pulse Generator / Module Standby and Software Reset Private Data
+ * struct cpg_mssr_priv - Clock Pulse Generator / Module Standby
+ *                        and Software Reset Private Data
  *
  * @rcdev: Optional reset controller entity
  * @dev: CPG/MSSR device