Hexagon: Add init_task and process functions

Hexagon: Add init_task and process functions

Fixed potential race-to-sleep condition in cpu_idle() and calling schedule
with irq's disabled.  I still have to have that extra enable/disbale in the
while() loop else the interrupt never gets serviced, and thus need_resched()
will always be false.

If called with interrupts disabled, our __vmwait() actually just returns
without servicing it.

Signed-off-by: Richard Kuo <rkuo@codeaurora.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>