pinctrl: renesas: Constify sh73a0_vccq_mc0_ops

The only usage of sh73a0_vccq_mc0_ops is to assign its address to the
ops field in the regulator_desc struct, which is a const pointer. Make
it const to allow the compiler to put it in read-only memory.

Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Link: https://lore.kernel.org/r/20201109221012.177478-1-rikard.falkeborn@gmail.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>