thunderbolt: Use weight constants in tb_usb3_consumed_bandwidth()

[ Upstream commit 4d24db0c ]

Instead of magic numbers use the constants we introduced in the previous
commit to make the code more readable. No functional changes.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Qin Wan <qin.wan@hp.com>
Signed-off-by: Alexandru Gagniuc <alexandru.gagniuc@hp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>