v4l2: Remove usage and definition of LOG_CAPS macro

v4l2: Remove usage and definition of LOG_CAPS macro

Unlike former definitions of LOG_CAPS, the current implementation simply
expands to GST_DEBUG_OBJECT. The LOG_CAPS macro is rarely used and most
uses duplicate already existing GST_DEBUG_OBJECT lines. Therefore, the
caps are often printed twice which unnecessarily clutters the debug log.

Replace LOG_CAPS calls with GST_DEBUG_OBJECT, remove LOG_CAPS calls, and
delete the definition of LOG_CAPS.

https://bugzilla.gnome.org/show_bug.cgi?id=776899