apq8064: Better (?) solution for the modem start race

Starting the modem as early as possible seems to do the trick.
Whatever's interfering with the startup "on boot" appears to
be something that can't run in parallel with modem init; if it
runs before or after, it starts up reliably.

Change-Id: I8d926c010909f71689c6b42384c631cd9dd73644