drm/amdgpu: Remove unused variable

Remove unused space_needed variable.

Fixes: 453f617a ("drm/amdgpu: Resize BAR0 to the maximum available size, even if it doesn't cover VRAM")
Signed-off-by: Nirmoy Das <nirmoy.das@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/413807/

drivers/gpu/drm/amd/amdgpu/amdgpu_device.c

@@ -1106,7 +1106,6 @@ void amdgpu_device_wb_free(struct amdgpu_device *adev, u32 wb)
  */
 int amdgpu_device_resize_fb_bar(struct amdgpu_device *adev)
 {
-	u64 space_needed = roundup_pow_of_two(adev->gmc.real_vram_size);
 	int rbar_size = pci_rebar_bytes_to_size(adev->gmc.real_vram_size);
 	struct pci_bus *root;
 	struct resource *res;