drm/msm/a6xx: add CONFIG_PM dependency

Selecting CONFIG_PM_GENERIC_DOMAINS causes a build failure when CONFIG_PM
is not enabled:

WARNING: unmet direct dependencies detected for PM_GENERIC_DOMAINS
  Depends on [n]: PM [=n]
  Selected by [m]:
  - DRM_MSM [=m] && HAS_IOMEM [=y] && DRM [=m] && (ARCH_QCOM [=y] || SOC_IMX5 || COMPILE_TEST [=y]) && COMMON_CLK [=y] && IOMMU_SUPPORT [=y] && (QCOM_OCMEM [=y] || QCOM_OCMEM [=y]=n) && (QCOM_LLCC [=n] || QCOM_LLCC [=n]=n) && (QCOM_COMMAND_DB [=y] || QCOM_COMMAND_DB [=y]=n) && DEVFREQ_GOV_SIMPLE_ONDEMAND [=y]

drivers/base/power/domain.c:654:13: error: use of undeclared identifier 'pm_wq'
        queue_work(pm_wq, &genpd->power_off_work);
                   ^
drivers/base/power/domain.c:853:26: error: no member named 'ignore_children' in 'struct dev_pm_info'
                if (!dev || dev->power.ignore_children)
                            ~~~~~~~~~~ ^

Fixes: c11fa120 ("drm/msm/a6xx: Use genpd notifier to ensure cx-gdsc collapse")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/528597/
Link: https://lore.kernel.org/r/20230324095502.3289094-1-arnd@kernel.orgSigned-off-by: Rob Clark <robdclark@chromium.org>

drivers/gpu/drm/msm/Kconfig

@@ -9,6 +9,7 @@ config DRM_MSM
 	depends on QCOM_OCMEM || QCOM_OCMEM=n
 	depends on QCOM_LLCC || QCOM_LLCC=n
 	depends on QCOM_COMMAND_DB || QCOM_COMMAND_DB=n
+	depends on PM
 	select IOMMU_IO_PGTABLE
 	select QCOM_MDT_LOADER if ARCH_QCOM
 	select REGULATOR