drm/amdgpu/userq: Use kvfree instead of kfree in amdgpu_userq_signal_ioctl

drm/amdgpu/userq: Use kvfree instead of kfree in amdgpu_userq_signal_ioctl

In function amdgpu_userq_signal_ioctl, drm_gem_objects_lookup allocates
memory via kvmalloc and hence when that memory is freed the memory
via kvfree.

Fixes: 4ca06f6fb45d ("drm/amdgpu/userq: Use drm_gem_objects_lookup in amdgpu_userq_signal_ioctl")
Signed-off-by: Sunil Khatri <sunil.khatri@amd.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>