BUG-1206 Use non-sign-extending shift

Just a precaution of intent: use shift which introduces 0, not
sign-dependent.

(cherry picked from commit ed6c85d06c4836904c12bf29812d3955353c26f5)
Signed-off-by: Robert Varga <robert.varga@pantheon.sk>
Signed-off-by: Michal Rehak <mirehak@cisco.com>
Change-Id: I644310fcc6c58cb942ddc25c6915a210ebb264be