clk: renesas: Make reset controller modemr register offset configurable

The MODEMR register offset changed on R8A779A0, make the MODEMR offset
configurable. Fill the offset in on all clock drivers. No functional
change.

Based off "clk: renesas: Make CPG Reset MODEMR offset accessible from
struct cpg_mssr_info" by Hai Pham <hai.pham.ud@renesas.com>

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>