drm/amd/display/dcn401: use pre-allocated temp structure for bounding box

This mirrors what the driver does for older DCN generations.

Should fix:
[   26.924055] BUG: sleeping function called from invalid context at include/linux/sched/mm.h:306
[   26.924060] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1022, name: modprobe
[   26.924063] preempt_count: 2, expected: 0
[   26.924064] RCU nest depth: 0, expected: 0
[   26.924066] Preemption disabled at:
[   26.924067] [<ffffffffc089e5e0>] dc_fpu_begin+0x30/0xd0 [amdgpu]
[   26.924322] CPU: 9 PID: 1022 Comm: modprobe Not tainted 6.8.0+ #20
[   26.924325] Hardware name: System manufacturer System Product Name/CROSSHAIR VI HERO, BIOS 6302 10/23/2018
[   26.924326] Call Trace:
[   26.924327]  <TASK>
[   26.924329]  dump_stack_lvl+0x37/0x50
[   26.924333]  ? dc_fpu_begin+0x30/0xd0 [amdgpu]
[   26.924589]  dump_stack+0x10/0x20
[   26.924592]  __might_resched+0x16a/0x1c0
[   26.924596]  __might_sleep+0x42/0x70
[   26.924598]  __kmalloc_node_track_caller+0x2ad/0x4b0
[   26.924601]  ? dm_helpers_allocate_gpu_mem+0x12/0x20 [amdgpu]
[   26.924855]  ? dcn401_update_bw_bounding_box+0x2a/0xf0 [amdgpu]
[   26.925122]  kmemdup+0x20/0x50
[   26.925124]  ? kernel_fpu_begin_mask+0x6b/0xe0
[   26.925127]  ? kmemdup+0x20/0x50
[   26.925129]  dcn401_update_bw_bounding_box+0x2a/0xf0 [amdgpu]
[   26.925393]  dc_create+0x311/0x670 [amdgpu]
[   26.925649]  amdgpu_dm_init+0x2aa/0x1fa0 [amdgpu]
[   26.925903]  ? irq_work_queue+0x38/0x50
[   26.925907]  ? vprintk_emit+0x1e7/0x270
[   26.925910]  ? dev_printk_emit+0x83/0xb0
[   26.925914]  ? amdgpu_device_rreg+0x17/0x20 [amdgpu]
[   26.926133]  dm_hw_init+0x14/0x30 [amdgpu]

v2: drop extra memcpy

Fixes: 669d6b07 ("drm/amd/display: avoid large on-stack structures")
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Suggested-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: George Zhang <george.zhang@amd.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: harry.wentland@amd.com
Cc: sunpeng.li@amd.com
Cc: Rodrigo.Siqueira@amd.com