regulator: anatop: Constify anatop_core_rops

regulator: anatop: Constify anatop_core_rops

anatop_core_rops is not modified and can therefore be made const which
allows the compiler to put it in read-only memory.

Before:
   text    data     bss     dec     hex filename
   4502     412       0    4914    1332 drivers/regulator/anatop-regulator.o

After:
   text    data     bss     dec     hex filename
   4634     280       0    4914    1332 drivers/regulator/anatop-regulator.o

Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Link: https://lore.kernel.org/r/20200617223247.25566-2-rikard.falkeborn@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>