rtl8723au: Convert __inline and __inline__ to standard inline

In addition, change "inline static" to the preferred "static inline" form.

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
rtl8723au: Remove all dead code inside #if 0 ... #endif

S/N goes up even more.

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>