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 <[e-mail]>
Closes: https://lore.kernel.org/oe-kbuild-all/[e-mail]/
Cc: Neil Armstrong <[e-mail]>
Signed-off-by: Douglas Anderson <[e-mail]>
Link: https://patch.msgid.link/20240830073511.1.Ib733229a8a19fad8179213c05e1af01b51e42328@changeid
Signed-off-by: Mark Brown <[e-mail]>

include/linux/regulator/consumer.h

···
 	return 0;
 }
 
+static inline int devm_regulator_bulk_get_const(
+	struct device *dev, int num_consumers,
+	const struct regulator_bulk_data *in_consumers,
+	struct regulator_bulk_data **out_consumers)
+{
+	return 0;
+}
+
 static inline int regulator_bulk_enable(int num_consumers,
 					struct regulator_bulk_data *consumers)
 {