brcmfmac: avoid gcc-5.1 warning

[Kalle Valo]

> gcc-5.0 gained a new warning in the fwsignal portion of the brcmfmac
> driver:
> 
> drivers/net/wireless/brcm80211/brcmfmac/fwsignal.c: In function 'brcmf_fws_txs_process':
> drivers/net/wireless/brcm80211/brcmfmac/fwsignal.c:1478:8: warning: 'skb' may be used uninitialized in this function [-Wmaybe-uninitialized]
> 
> This is a false positive, and marking the brcmf_fws_hanger_poppkt function
> as 'static inline' makes the warning go away. I have checked the object
> file output and while a little code gets moved around, the size of
> the binary remains identical.
> 
> Signed-off-by: Arnd Bergmann <arnd at arndb.de>

Thanks, applied to wireless-drivers-next.git.

Kalle Valo