[ALSA] #3/4 for Zoom Video - change Hardware Volume interrupt handling

Modules: ES18xx driver

Third of 4 es18xx.c patches culminating in Zoom Video support.

This patch changes the Hardware Volume support to reflect the fact that
not all of the
supported chipsets have seperate registers dedicated to the Hardware
Volume inputs. Although
all the chipsets can generate an HWV interrupt whenever a Hardware
Volume input is received
only those with seperate HWV registers can split the HWV registers from
the Master volume
registers.

Testing:
This work was initially done on the source from the Debian Sarge ALSA
package, then tested
on an ES1879 and an ES1878 machine. Patches were created against the
Sarge code and then edited
to apply correctly to the ALSA cvs code. Lastly the patched ALSA cvs
code was test for
successful compilation. No additional testing was done on the ALSA cvs
version.

Signed-off-by: Mark Salazar <markTheCoder@justmyself.net>
Signed-off-by: Takashi Iwai <tiwai@suse.de>