msm_fb: allow negative x,y quickpeek buffer coordinates

By allowing the x,y coordinates of a quickpeek buffer to be signed we are
allowing for buffers to be partially drawn to the viewable screen area
(i.e. have a buffer be clipped to the edge of the screen).

Change-Id: I9c67b950c51a0c2d9a96836c4a9ace32f7aca3b9
Signed-off-by: Joe Swantek <jswantek@motorola.com>
Reviewed-on: http://gerrit.pcs.mot.com/623361
SLTApproved: Slta Waiver <sltawvr@motorola.com>
Tested-by: Jira Key <jirakey@motorola.com>
Reviewed-by: Jared Suttles <jsuttles@motorola.com>
Reviewed-by: Bang Nguyen <bangnguyen@motorola.com>
Reviewed-by: Patrick Auchter <auchter@motorola.com>
Reviewed-by: Fred Fettinger <fettinge@motorola.com>
Reviewed-by: George Standish <george.standish@motorola.com>
Reviewed-by: Stephen Rossbach <rossbach@motorola.com>
Submit-Approved: Jira Key <jirakey@motorola.com>
(cherry picked from commit 0d4ffe9a0fcc367876d5ed0b7c4c94e61bc89f09)
Reviewed-on: http://gerrit.pcs.mot.com/625598
Reviewed-by: Upgrade Build <dbbuild@motorola.com>
SLTApproved: Upgrade Build <dbbuild@motorola.com>
Submit-Approved: Upgrade Build <dbbuild@motorola.com>
Tested-by: Upgrade Build <dbbuild@motorola.com>