alsa-lib: Change function type to "static __inline__"

alsa-lib: Change function type to "static __inline__"

"extern __inline__ function()" is the inlined version that
can be used in this compilation unit, but there will be another
definition of this function somewhere, so compiler will not emit
any code for the function body. This causes problem in -O0,
where functions are never inlined, the function call is preserved,
but linker can't find the symbol, thus the error happens.

since no packages provide atomic_add and atomic_sub, and -O0
Optimize is hoped to keep for debug, we can change extern to
static to fix this problem.

(From OE-Core rev: d0af30c92fdea6f48afb4ab1fde69f1b636e8203)

Signed-off-by: Roy.Li <rongqing.li@windriver.com>
Signed-off-by: Jesse Zhang <sen.zhang@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>