ladspa-sink: Add sink_master argument to enable filter-apply to load the module

ladspa-sink: Add sink_master argument to enable filter-apply to load the module

Currently, module-filter-apply cannot load module-ladspa-sink because filter-apply
provides the argument "sink_master" but ladspa-sink expects "master" instead.

Therefore this patch adds the sink_master argument to module-ladspa-sink.

Additionally, the autoloaded argument was also added.

This patch based on:
https://cgit.freedesktop.org/pulseaudio/pulseaudio/commit/?id=145da09aca8b54d611999ebf661b05ceb9e1c62f

ladspa-sink, virtual-surround-sink: fix master sink argument handling

The old code worked incorrectly in several situations. For example,
trying to use the "master" argument wouldn't work, because if
"sink_master" wasn't specified, pa_namereg_get() would pick the default
sink as the master sink.

This patch based on:
https://cgit.freedesktop.org/pulseaudio/pulseaudio/commit/?id=65f7ca44148e8c79fa965a6ecbc889e3f9668178

Signed-off-by: KimJeongYeon <jeongyeon.kim@samsung.com>
Change-Id: I15382f0f2551bcd2d3bcb9bf117914ed2cc3e5ff