Revert "ARM: dts: msm: Remove unused gpio from mdm9x40 DT"

This reverts commit <94086aa1>.

After applying pinctrl sleep configuration for QCA6174,
QCA6174 chip is not coming into proper power state which
result stability issue. To avoid crash adding gpio node
in DT.

Change-Id: Iaa599637cdc371a780f0b09e0fc0eda9228b512e
CRs-Fixed: 1059765
Signed-off-by: Hardik Kantilal Patel <hkpatel@codeaurora.org>