clk: renesas: Add register pointers into struct cpg_mssr_info

Base on Linux v5.10-rc2, commit 8b652aa8a1fb by Yoshihiro Shimoda
To support other register layouts in the future, add register pointers
of {control,status,reset,reset_clear}_regs into struct cpg_mssr_info

Signed-off-by: Hai Pham <hai.pham.ud@renesas.com>
Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>