timekeeping: Fix time moving backwards

Changed the calculation logic that sometimes calculates
the time wrong.

Sometimes there is an overflow when the tv_nsec field in
the timespec structure is being added since it is 32-bit.

To resolve this issue nsec variable is being added first
so that the addition is performed in 64 bit signed format.

Bug 1217429

Change-Id: I9c65da88f02596ba73c47be6342ed909e650db22
Signed-off-by: Ajay Nandakumar <anandakumarm@nvidia.com>
Reviewed-on: http://git-master/r/195092
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Prashant Gaikwad <pgaikwad@nvidia.com>
Reviewed-by: Shridhar Rasal <srasal@nvidia.com>
Reviewed-by: Bo Yan <byan@nvidia.com>
GVS: Gerrit_Virtual_Submit
Reviewed-by: Bharat Nihalani <bnihalani@nvidia.com>
Tested-by: Shridhar Rasal <srasal@nvidia.com>
TouchWake implementation v1.0 (Yank555.lu)

- Finger and Pen working

Issues :

- Finger detection only works after screen is off for 1-2 seconds
- Call detection missing to avoid turning the screen on when placing the device close to the ear

Conflicts:

	drivers/misc/Makefile
TouchWake implementation v1.1 (Yank555.lu)

- Finger and Pen working
- Call detection working through proxy detection

Issues left to resolve :

- Finger detection only works after screen is off for 1-2 seconds

 * SysFs interface :
 *
 * /sys/class/misc/touchwake/enabled (rw) : 0 - on / 1 - off
 *
 *     Enable / Disable TouchWake
 *
 *     NB: Turning the device off with the power key will disable touchwake
 *
 * /sys/class/misc/touchwake/delay (rw) :
 *
 *     Sets the delay in ms to keep touchscreen / pen actively listening for touch after screen goes off
 *
 *     NB: A value of 0 equals "infinite", will drain battery !
 *
 * /sys/class/misc/touchwake/proximity_threshold (rw) :
 *
 *     Sets the threshold from which to consider the proxy triggered (which will disable touchwake)
 *
 *     NB: This serves as a kind of in-call detection to not turn the screen on during a call when placing
 *         the device to the ear
 *
 * /sys/class/misc/touchwake/version (ro) :
 *
 *     Display the current version of the eXtended ConTRoLs
 *
 * /sys/class/misc/touchwake/debug (ro) :
 *
 *     Display debugging info (only if debugging is active at compilation time)

Conflicts:

	drivers/input/touchscreen/wacom/wacom_i2c.c