Remove unnecessary right padding from time picker

Symptom:
When the device language was set to Spanish, "A.M." label was not fully
displayed on the time picker widget. "M." was lacked.

Root cause:
There are unnecessary right paddings on the layout definition of time
picker. It uselessly consumes the room for ampm_layout.

Bug: 64498105
Change-Id: Ie52fafc0fb7d6d6ea5b0ca2eaeb53755d4aebc19