touchscreen: fts: Fix array OOB issues in sysfs diag test interface.

fts sysfs store callback was not taking care of edge cases where input
length is greater than the command buffer size. This CL fixes these
corner array OOB cases and improves/simplifies the string parsing logic.

Bug: 120141999
Bug: 120141031
Bug: 120279144

Change-Id: If08a2de0a5352523e7910e5676b378b824658dd0
Signed-off-by: Biswajit Dash <bisdash@google.com>
1 file changed