staging: brcm80211: remove 'used' keyword from function ai_ispcie()

The function ai_ispcie() is a static function that is currently being
called from the c sources in the driver. Side-effect of the keyword
is that warning will suppressed when this function is no longer used.
As there is no assembly code using this function, the keyword is removed.
Signed-off-by: NArend van Spriel <arend@broadcom.com>
Reviewed-by: NFranky Lin <frankyl@broadcom.com>
Reviewed-by: NRoland Vossen <rvossen@broadcom.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/staging/brcm80211/brcmsmac/aiutils.c

@@ -2028,7 +2028,7 @@ static char *ai_devpathvar(struct si_pub *sih, char *var, int len,
 }
 
 /* return true if PCIE capability exists in the pci config space */
-static __used bool ai_ispcie(si_info_t *sii)
+static bool ai_ispcie(si_info_t *sii)
 {
 	u8 cap_ptr;