ARM: dts: msm: update out-strength of GPIO 15 for apq8084

Currently, the out strength of GPIO 15 is medium. This would result in
strange noise during UI navigation due to HW issues. Change out strength
of GPIO 15 to high could solve this issue. Hence change the out strength
of GPIO 15 to high strength.

Change-Id: Iff69c0d4d704aff8abc04b45d957854cd311b0d5
CRs-fixed: 686947
Signed-off-by: Ke Liu <keliu@codeaurora.org>