drm: Drop ARCH_MULTIPLATFORM from dependencies

Some of these dependencies used to be sensible when only a small part of
the platforms supported by ARCH=arm could be compiled together in a
single kernel image. Nowadays ARCH_MULTIPLATFORM is only used as a guard
for kernel options incompatible with a multiplatform image. See commit
84fc86360623 ("ARM: make ARCH_MULTIPLATFORM user-visible") for some more
details.

Signed-off-by: Uwe Kleine-König <[e-mail]>
Acked-by: Arnd Bergmann <[e-mail]>
Reviewed-by: Javier Martinez Canillas <[e-mail]>
Reviewed-by: Philipp Zabel <[e-mail]>
Signed-off-by: Javier Martinez Canillas <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/exynos/Kconfig

···
 config DRM_EXYNOS
 	tristate "DRM Support for Samsung SoC Exynos Series"
 	depends on OF && DRM && COMMON_CLK
-	depends on ARCH_S3C64XX || ARCH_S5PV210 || ARCH_EXYNOS || ARCH_MULTIPLATFORM || COMPILE_TEST
+	depends on ARCH_S3C64XX || ARCH_S5PV210 || ARCH_EXYNOS || COMPILE_TEST
 	depends on MMU
 	select DRM_DISPLAY_HELPER if DRM_EXYNOS_DP
 	select DRM_KMS_HELPER

drivers/gpu/drm/imx/ipuv3/Kconfig

···
 	select DRM_KMS_HELPER
 	select VIDEOMODE_HELPERS
 	select DRM_GEM_DMA_HELPER
-	depends on DRM && (ARCH_MXC || ARCH_MULTIPLATFORM || COMPILE_TEST)
+	depends on DRM && (ARCH_MXC || COMPILE_TEST)
 	depends on IMX_IPUV3_CORE
 	help
 	  enable i.MX graphics support

drivers/gpu/drm/omapdrm/Kconfig

···
 config DRM_OMAP
 	tristate "OMAP DRM"
 	depends on DRM && OF
-	depends on ARCH_OMAP2PLUS || ARCH_MULTIPLATFORM
+	depends on ARCH_OMAP2PLUS
 	select DRM_KMS_HELPER
 	select VIDEOMODE_HELPERS
 	select HDMI

drivers/gpu/drm/sti/Kconfig

···
 # SPDX-License-Identifier: GPL-2.0-only
 config DRM_STI
 	tristate "DRM Support for STMicroelectronics SoC stiH4xx Series"
-	depends on OF && DRM && (ARCH_STI || ARCH_MULTIPLATFORM)
+	depends on OF && DRM && ARCH_STI
 	select RESET_CONTROLLER
 	select DRM_KMS_HELPER
 	select DRM_GEM_DMA_HELPER

drivers/gpu/drm/stm/Kconfig

···
 # SPDX-License-Identifier: GPL-2.0-only
 config DRM_STM
 	tristate "DRM Support for STMicroelectronics SoC Series"
-	depends on DRM && (ARCH_STM32 || ARCH_MULTIPLATFORM)
+	depends on DRM && ARCH_STM32
 	select DRM_KMS_HELPER
 	select DRM_GEM_DMA_HELPER
 	select DRM_PANEL_BRIDGE

drivers/gpu/ipu-v3/Kconfig

···
 # SPDX-License-Identifier: GPL-2.0-only
 config IMX_IPUV3_CORE
 	tristate "IPUv3 core support"
-	depends on SOC_IMX5 || SOC_IMX6Q || ARCH_MULTIPLATFORM || COMPILE_TEST
+	depends on SOC_IMX5 || SOC_IMX6Q || COMPILE_TEST
 	depends on DRM || !DRM # if DRM=m, this can't be 'y'
 	select BITREVERSE
 	select GENERIC_ALLOCATOR if DRM