Atmel MXT touchscreen: increase reset timeouts

There is a more complete atmel patch-series out by Nick Dyer that fixes
this and other things, but in the meantime this is the minimal thing to
get the touchscreen going on (at least my) Pixel Chromebook.

Not that I want my dirty fingers near that beautiful screen, but it
seems that a non-initialized touchscreen will also end up being a
constant wakeup source, so you have to disable it to go to sleep. And
it's easier to just fix the initialization sequence.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>