drm/vmwgfx: Honor the sg list segment size limitation

[ Upstream commit bde15555 ]

When building sg tables, honor the device sg list segment size limitation.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Deepak Rawat <drawat@vmware.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>