intel_idle: shrink states tables

intel_idle: shrink states tables

There is no reason to define CPUIDLE_STATE_MAX (currently 10) entries
in states tables if the driver always stops iterating over table when
it encounters first .enter == NULL entry.

$ size drivers/idle/intel_idle.o.*
   text    data     bss     dec     hex filename
   2886    5440      32    8358    20a6 drivers/idle/intel_idle.o.before
   2886    3752      32    6670    1a0e drivers/idle/intel_idle.o.after

Signed-off-by: Bartlomiej Zolnierkiewicz <[email protected]>
Signed-off-by: Kyungmin Park <[email protected]>
Acked-by: Daniel Lezcano <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>