drivers/staging/rtl8192u/r8192U_wx.c: fix warnings issued by sparse

This minor patch motivated by eudyptula challenge fixes the following warnings issued
by `sparse' in drivers/staging/rtl8192u/r8192U_wx.c:
 .../r8192U_wx.c:27:5: warning: symbol 'rtl8180_rates' was not declared. Should it be static?
 .../r8192U_wx.c:961:22: warning: symbol 'r8192_get_wireless_stats' was not declared. Should it be static?
 .../r8192U_wx.c:990:24: warning: symbol 'r8192_wx_handlers_def' was not declared. Should it be static?
Signed-off-by: Ovidiu Toader <ovi@phas.ubc.ca>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8192u/r8192U_wx.c

@@ -22,9 +22,10 @@
 #include "r8192U_hw.h"
 
 #include "dot11d.h"
+#include "r8192U_wx.h"
 
 #define RATE_COUNT 12
-u32 rtl8180_rates[] = {1000000, 2000000, 5500000, 11000000,
+static const u32 rtl8180_rates[] = {1000000, 2000000, 5500000, 11000000,
 	6000000, 9000000, 12000000, 18000000, 24000000, 36000000, 48000000, 54000000};