power: supply: samsung-sdi-battery: Constify struct power_supply_maintenance_charge_table

'struct power_supply_maintenance_charge_table' is not modified in this
driver.

Constifying this structure moves some data to a read-only section, so
increase overall security.

In order to do it, some code also needs to be adjusted to this new const
qualifier.

On a x86_64, with allmodconfig:
Before:
======
$ size drivers/power/supply/samsung-sdi-battery.o
   text	   data	    bss	    dec	    hex	filename
   4055	   4584	      0	   8639	   21bf	drivers/power/supply/samsung-sdi-battery.o

After:
=====
$ size drivers/power/supply/samsung-sdi-battery.o
   text	   data	    bss	    dec	    hex	filename
   4087	   4552	      0	   8639	   21bf	drivers/power/supply/samsung-sdi-battery.o

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/6caafd0ac2556a40405273b1a4badc508ea8e9b0.1719125040.git.christophe.jaillet@wanadoo.fr


Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>