regulator: core: Stub devm_regulator_bulk_get_const() if !CONFIG_REGULATOR

regulator: core: Stub devm_regulator_bulk_get_const() if !CONFIG_REGULATOR

When adding devm_regulator_bulk_get_const() I missed adding a stub for
when CONFIG_REGULATOR is not enabled. Under certain conditions (like
randconfig testing) this can cause the compiler to reports errors
like:

  error: implicit declaration of function 'devm_regulator_bulk_get_const';
  did you mean 'devm_regulator_bulk_get_enable'?

Add the stub.

Fixes: 1de452a0edda ("regulator: core: Allow drivers to define their init data as const")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202408301813.TesFuSbh-lkp@intel.com/
Cc: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patch.msgid.link/20240830073511.1.Ib733229a8a19fad8179213c05e1af01b51e42328@changeid
Signed-off-by: Mark Brown <broonie@kernel.org>