ALSA: Make pcm.h self-contained

Move the macros depending on snd_mask_min() and co out of pcm.h into
pcm_params.h.  Otherwise using some params_*() macros will give comiple
errors without inclusion of pcm_params.h.

Also use hw_param_interval_c() and hw_param_mask_c() for const pointer.

Reported-by: Tim Blechmann <tim@klingt.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>