drm/mediatek: stop selecting foreign drivers

The PHY portion of the mediatek hdmi driver was originally part of
the driver it self and later split out into drivers/phy, which a
'select' to keep the prior behavior.

However, this leads to build failures when the PHY driver cannot
be built:

WARNING: unmet direct dependencies detected for PHY_MTK_HDMI
  Depends on [n]: (ARCH_MEDIATEK || COMPILE_TEST [=y]) && COMMON_CLK [=y] && OF [=y] && REGULATOR [=n]
  Selected by [m]:
  - DRM_MEDIATEK_HDMI [=m] && HAS_IOMEM [=y] && DRM [=m] && DRM_MEDIATEK [=m]
ERROR: modpost: "devm_regulator_register" [drivers/phy/mediatek/phy-mtk-hdmi-drv.ko] undefined!
ERROR: modpost: "rdev_get_drvdata" [drivers/phy/mediatek/phy-mtk-hdmi-drv.ko] undefined!

The best option here is to just not select the phy driver and leave that
up to the defconfig. Do the same for the other PHY and memory drivers
selected here as well for consistency.

Fixes: a481bf2 ("drm/mediatek: Separate mtk_hdmi_phy to an independent module")
Signed-off-by: Arnd Bergmann <[email protected]>
Reviewed-by: AngeloGioacchino Del Regno <[email protected]>
Reviewed-by: CK Hu <[email protected]>
Link: https://patchwork.kernel.org/project/dri-devel/patch/[email protected]/
Signed-off-by: Chun-Kuang Hu <[email protected]>

drivers/gpu/drm/mediatek/Kconfig

@@ -14,9 +14,6 @@ config DRM_MEDIATEK
 	select DRM_BRIDGE_CONNECTOR
 	select DRM_MIPI_DSI
 	select DRM_PANEL
-	select MEMORY
-	select MTK_SMI
-	select PHY_MTK_MIPI_DSI
 	select VIDEOMODE_HELPERS
 	help
 	  Choose this option if you have a Mediatek SoCs.
@@ -27,7 +24,6 @@ config DRM_MEDIATEK
 config DRM_MEDIATEK_DP
 	tristate "DRM DPTX Support for MediaTek SoCs"
 	depends on DRM_MEDIATEK
-	select PHY_MTK_DP
 	select DRM_DISPLAY_HELPER
 	select DRM_DISPLAY_DP_HELPER
 	select DRM_DISPLAY_DP_AUX_BUS
@@ -38,6 +34,5 @@ config DRM_MEDIATEK_HDMI
 	tristate "DRM HDMI Support for Mediatek SoCs"
 	depends on DRM_MEDIATEK
 	select SND_SOC_HDMI_CODEC if SND_SOC
-	select PHY_MTK_HDMI
 	help
 	  DRM/KMS HDMI driver for Mediatek SoCs