drm/admgpu: replace kmalloc() and memcpy() with kmemdup()

drm/admgpu: replace kmalloc() and memcpy() with kmemdup()

The static analyser tool gave the following advice:

./drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c:1266:7-14: WARNING opportunity for kmemdup

 → 1266         tmp = kmalloc(used_size, GFP_KERNEL);
   1267         if (!tmp)
   1268                 return -ENOMEM;
   1269
 → 1270         memcpy(tmp, &host_telemetry->body.error_count, used_size);

Replacing kmalloc() + memcpy() with kmemdump() doesn't change semantics.
Original code works without fault, so this is not a bug fix but proposed improvement.

Link: https://lwn.net/Articles/198928/
Fixes: 84a2947ecc85 ("drm/amdgpu: Implement virt req_ras_err_count")
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: Xinhui Pan <Xinhui.Pan@amd.com>
Cc: David Airlie <airlied@gmail.com>
Cc: Simona Vetter <simona@ffwll.ch>
Cc: Zhigang Luo <Zhigang.Luo@amd.com>
Cc: Victor Skvortsov <victor.skvortsov@amd.com>
Cc: Hawking Zhang <Hawking.Zhang@amd.com>
Cc: Lijo Lazar <lijo.lazar@amd.com>
Cc: Yunxiang Li <Yunxiang.Li@amd.com>
Cc: Jack Xiao <Jack.Xiao@amd.com>
Cc: Vignesh Chander <Vignesh.Chander@amd.com>
Cc: Danijel Slivka <danijel.slivka@amd.com>
Cc: amd-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Signed-off-by: Mirsad Todorovac <mtodorovac69@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>