[ALSA] maestro3.c: fix BUG, optimization
[ALSA] maestro3.c: fix BUG, optimization

- fix brown-paper-bag locking bug (lock() / return / unlock())
- improve central function snd_m3_update_ptr()
  (avoid expensive integer divisions)
- add cpu_relax() to busy-wait I/O loop as recommended
  (does this require special macro support in ALSA for older kernels??)
- constify several structs
- spelling updates

Signed-off-by: Andreas Mohr <dbd122ef7b6a09ffecf5db9c9296320f3c94e707@lisas.de>
Signed-off-by: Takashi Iwai <4596b3305151c7ee743192a95d394341e3d3b644@suse.de>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas