drm/amd/display: dynamically allocate dml2_configuration_options structures

This structure is too large to fit on a stack, as shown by the
newly introduced warnings from a recent code change:

drivers/gpu/drm/amd/amdgpu/../display/dc/resource/dcn32/dcn32_resource.c: In function 'dcn32_update_bw_bounding_box':
drivers/gpu/drm/amd/amdgpu/../display/dc/resource/dcn32/dcn32_resource.c:2019:1: error: the frame size of 1180 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
drivers/gpu/drm/amd/amdgpu/../display/dc/resource/dcn321/dcn321_resource.c: In function 'dcn321_update_bw_bounding_box':
drivers/gpu/drm/amd/amdgpu/../display/dc/resource/dcn321/dcn321_resource.c:1597:1: error: the frame size of 1180 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]
drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_state.c: In function 'dc_state_create':
drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_state.c:219:1: error: the frame size of 1184 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]

Instead of open-coding the assignment of a large structure to a stack
variable, use an explicit kmemdup() in each case to move it off the stack.

Fixes: e779f458 ("drm/amd/display: Add handling for DC power mode")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>