power: regulator: qcom-rpmh-regulator: add build infra

Add Kconfig and Makefile entries for this driver now that it can build
for U-Boot.

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Caleb Connolly <caleb.connolly@linaro.org>
diff --git a/drivers/power/regulator/Kconfig b/drivers/power/regulator/Kconfig
index 102ec7b..bc061c2 100644
--- a/drivers/power/regulator/Kconfig
+++ b/drivers/power/regulator/Kconfig
@@ -216,6 +216,14 @@
 	features for gpio regulators. The driver implements get/set for
 	voltage value.
 
+config DM_REGULATOR_QCOM_RPMH
+	bool "Enable driver model for Qualcomm RPMh regulator"
+	depends on DM_REGULATOR && QCOM_RPMH
+	---help---
+	  Enable support for the Qualcomm RPMh regulator. The driver
+	  implements get/set api for a limited set of regulators used
+	  by u-boot.
+
 config SPL_DM_REGULATOR_GPIO
 	bool "Enable Driver Model for GPIO REGULATOR in SPL"
 	depends on DM_REGULATOR_GPIO && SPL_GPIO