audio: Replace static functions in header file by macros, remove GCC_ATTR

Using macros instead of static functions for dolog and for ldebug
simplifies the code and can also reduce the total code size.

GCC_ATTR was only used in audio_int.h, so it is now unused and
the definition can be removed from compiler.h.

Signed-off-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>