ALSA: HDA: hdac_ext_stream: use consistent prefixes for variables

ALSA: HDA: hdac_ext_stream: use consistent prefixes for variables

The existing code maximizes confusion by using 'stream' and 'hstream'
variables of different types. Examples:

struct hdac_stream *stream;
struct hdac_ext_stream *stream;
struct hdac_stream *hstream;
struct hdac_ext_stream *hstream;

with some additional copy/paste remains:
struct hdac_ext_stream *azx_dev;

This patch suggests a consistent naming across all 'hdac_ext_stream'
functions. The convention is:

struct hdac_stream *hstream;
struct hdac_ext_stream *hext_stream;

No functionality change - just renaming of variables and more
consistent indentation.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@intel.com>
Link: https://lore.kernel.org/r/20211216231128.344321-3-pierre-louis.bossart@linux.intel.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>