staging: rtl8712, rtl8712: avoid lots of build warnings

The rtl8712 driver has an 'extern inline' function that contains an
'if', which causes lots of warnings with CONFIG_PROFILE_ALL_BRANCHES
overriding the definition of 'if':

drivers/staging/rtl8712/ieee80211.h:759:229: warning: '______f' is static but declared in inline function 'ieee80211_get_hdrlen' which is not static [enabled by default]

This changes the driver to use 'static inline' instead, which happens
to be the correct annotation anyway.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Florian Schilhabel <florian.c.schilhabel@googlemail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/staging/rtl8712/ieee80211.h b/drivers/staging/rtl8712/ieee80211.h
index da4000e..8269be8 100644
--- a/drivers/staging/rtl8712/ieee80211.h
+++ b/drivers/staging/rtl8712/ieee80211.h
@@ -734,7 +734,7 @@
 #define IEEE_G            (1<<2)
 #define IEEE_MODE_MASK    (IEEE_A|IEEE_B|IEEE_G)
 
-extern inline int ieee80211_is_empty_essid(const char *essid, int essid_len)
+static inline int ieee80211_is_empty_essid(const char *essid, int essid_len)
 {
 	/* Single white space is for Linksys APs */
 	if (essid_len == 1 && essid[0] == ' ')
@@ -748,7 +748,7 @@
 	return 1;
 }
 
-extern inline int ieee80211_get_hdrlen(u16 fc)
+static inline int ieee80211_get_hdrlen(u16 fc)
 {
 	int hdrlen = 24;