drm: panel: mantix: Speed up display init

Use a timeout value closer to the data sheet rather than
the vendor code. This saves off almost a second.

Signed-off-by: Guido Günther <guido.gunther@puri.sm>
2 jobs for mrs/unblank-speedup in 79 minutes and 38 seconds (queued for 17 minutes and 41 seconds)