regulator: qcom-rpmh: add QCOM_COMMAND_DB dependency

A built-in regulator driver cannot link against a modular cmd_db driver:

qcom-rpmh-regulator.c:(.text+0x174): undefined reference to `cmd_db_read_addr'

There is already a dependency for RPMh, so add another one of this
type for cmd_db.

Fixes: 34c5aa26 ("regulator: Kconfig: Fix REGULATOR_QCOM_RPMH dependencies to avoid build error")
Fixes: 46fc033e ("regulator: add QCOM RPMh regulator driver")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20201230145712.3133110-1-arnd@kernel.orgSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/Kconfig

@@ -881,6 +881,7 @@ config REGULATOR_QCOM_RPM
 config REGULATOR_QCOM_RPMH
 	tristate "Qualcomm Technologies, Inc. RPMh regulator driver"
 	depends on QCOM_RPMH || (QCOM_RPMH=n && COMPILE_TEST)
+	depends on QCOM_COMMAND_DB || (QCOM_COMMAND_DB=n && COMPILE_TEST)
 	help
 	  This driver supports control of PMIC regulators via the RPMh hardware
 	  block found on Qualcomm Technologies Inc. SoCs.  RPMh regulator