ARM: dts: msm: fix ab/ib values for ddr vote on sdxpoorwills

AB/IB values currently used do not reflect the actual frequency
values. Make changes to use right buswdith (4) bits to measure
ab/ib values.

Change-Id: I8291b2dc42a20c1affa39981eb1a134599b3fce6
Acked-by: Chaitanya Pratapa <cpratapa@qti.qualcomm.com>
Signed-off-by: Mohammed Javid <mjavid@codeaurora.org>