drm/amdgpu: fix license on Kconfig and Makefiles

amdgpu is MIT licensed.

Fixes: ec8f24b7 ("treewide: Add SPDX license identifier - Makefile/Kconfig")
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/acp/Kconfig

-# SPDX-License-Identifier: GPL-2.0-only
+# SPDX-License-Identifier: MIT
 menu "ACP (Audio CoProcessor) Configuration"
 
 config DRM_AMD_ACP

drivers/gpu/drm/amd/amdgpu/Kconfig

-# SPDX-License-Identifier: GPL-2.0-only
+# SPDX-License-Identifier: MIT
 config DRM_AMDGPU_SI
 	bool "Enable amdgpu support for SI parts"
 	depends on DRM_AMDGPU

drivers/gpu/drm/amd/amdkfd/Kconfig

-# SPDX-License-Identifier: GPL-2.0-only
+# SPDX-License-Identifier: MIT
 #
 # Heterogenous system architecture configuration
 #

drivers/gpu/drm/amd/display/Kconfig

-# SPDX-License-Identifier: GPL-2.0-only
+# SPDX-License-Identifier: MIT
 menu "Display Engine Configuration"
 	depends on DRM && DRM_AMDGPU
 

drivers/gpu/drm/amd/display/dc/dcn20/Makefile

+# SPDX-License-Identifier: MIT
 #
 # Makefile for DCN.
 

drivers/gpu/drm/amd/display/dc/dcn21/Makefile

+# SPDX-License-Identifier: MIT
 #
 # Makefile for DCN21.
 

drivers/gpu/drm/amd/display/dc/dsc/Makefile

+# SPDX-License-Identifier: MIT
 #
 # Makefile for the 'dsc' sub-component of DAL.