input: gen_vkeys: squash commit from 3.14-kernel

Squash and apply the following changes taken from the msm-3.14
kernel branch as of msm-3.14
commit 8139d0b4e7a6d ("ARM: dts: msm: Set flag to manage clks")

c24a3df input: gen_vkeys: Make y_offset an optional property
bb2ac18 vkeys: gen_vkeys: Add key position offset
1a6d213 input: Add support for virtual key generation

Fix checkpatch errors.

Change-Id: Ie0e14d201a42632af57ff23dc85cec8881125e5a
Signed-off-by: Alex Sarraf <asarraf@codeaurora.org>
Signed-off-by: Venkata Prahlad Valluru <vvalluru@codeaurora.org>