regulator: max8998: max8998_set_current_limit() can be static

Fixes: 4ffea5e0 ("regulator: max8998: Add charger regulator")
Signed-off-by: kbuild test robot <lkp@intel.com>
Link: https://lore.kernel.org/r/20200530130314.GA73557@d7d8dbfb64ff


Signed-off-by: Mark Brown <broonie@kernel.org>