drm/amdgpu: add missing license to some files

The driver is MIT, so add the licenses.

Bug: https://gitlab.freedesktop.org/drm/amd/-/issues/2265
Acked-by: Luben Tuikov <luben.tuikov@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/clk_mgr/dcn30/dcn30_smu11_driver_if.h

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: MIT
 // This is a stripped-down version of the smu11_driver_if.h file for the relevant DAL interfaces.
 
 #define SMU11_DRIVER_IF_VERSION 0x40

drivers/gpu/drm/amd/display/dc/clk_mgr/dcn32/dcn32_smu13_driver_if.h

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: MIT
 // This is a stripped-down version of the smu13_driver_if.h file for the relevant DAL interfaces.
 
 #define SMU13_DRIVER_IF_VERSION  0x18

drivers/gpu/drm/amd/include/asic_reg/dcn/dcn_3_0_0_offset.h

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: MIT
 #ifndef _dcn_3_0_0_OFFSET_HEADER
 #define _dcn_3_0_0_OFFSET_HEADER
 

drivers/gpu/drm/amd/include/asic_reg/dcn/dcn_3_0_0_sh_mask.h

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: MIT
 #ifndef _dcn_3_0_0_SH_MASK_HEADER
 #define _dcn_3_0_0_SH_MASK_HEADER
 

drivers/gpu/drm/amd/include/yellow_carp_offset.h

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: MIT
 #ifndef YELLOW_CARP_OFFSET_H
 #define YELLOW_CARP_OFFSET_H