regulator: Kconfig: Fix REGULATOR_QCOM_RPMH dependencies to avoid build error

The kernel test robot reported the following build error:

All errors (new ones prefixed by >>):

   xtensa-linux-ld: drivers/regulator/qcom-rpmh-regulator.o: in function `rpmh_regulator_vrm_get_voltage_sel':
   qcom-rpmh-regulator.c:(.text+0x270): undefined reference to `rpmh_write'
   xtensa-linux-ld: drivers/regulator/qcom-rpmh-regulator.o: in function `rpmh_regulator_send_request':
   qcom-rpmh-regulator.c:(.text+0x2f2): undefined reference to `rpmh_write'
   xtensa-linux-ld: drivers/regulator/qcom-rpmh-regulator.o: in function `rpmh_regulator_vrm_get_voltage_sel':
>> qcom-rpmh-regulator.c:(.text+0x274): undefined reference to `rpmh_write_async'
   xtensa-linux-ld: drivers/regulator/qcom-rpmh-regulator.o: in function `rpmh_regulator_send_request':
   qcom-rpmh-regulator.c:(.text+0x2fc): undefined reference to `rpmh_write_async'

Which is due to REGULATOR_QCOM_RPMH depending on
QCOM_RPMH || COMPILE_TEST. The problem is that QOM_RPMH can now
be a module, which in that case requires REGULATOR_QCOM_RPMH=m
to build.

However, if COMPILE_TEST is enabled, REGULATOR_QCOM_RPMH can be
set to =y while QCOM_RPMH=m which will cause build failures.

The fix here is to add (QCOM_RPMH=n && COMPILE_TEST) to the
dependency.

Feedback would be appreciated!

Cc: Todd Kjos <tkjos@google.com>
Cc: Saravana Kannan <saravanak@google.com>
Cc: Andy Gross <agross@kernel.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Rajendra Nayak <rnayak@codeaurora.org>
Cc: Maulik Shah <mkshah@codeaurora.org>
Cc: Stephen Boyd <swboyd@chromium.org>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: linux-arm-msm@vger.kernel.org
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20201123222359.103822-1-john.stultz@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>