make splash_progress lock to screen width on repeated calls
when calling splash, splash_progress repeatedly text rearranges and
the width changes leaving artifacts on the screen from the previously
displayed prompt
save the max width seen between calls to ensure the splash
prompt is never more narrow.
Height could be stored in a
similar manner but I deemed it unnecessary as typically the
text gets longer and the prompt increases in height
while the reflow causes the prompt to get more narrow.
keep track of the current activity and reset the max_width
when activities change (except bootloader)
Change-Id: I3303bd9135ab1d7bcf28bd5c28d0ab5346bf2697