Staging: rtl8192su: add linux/vmalloc.h

Some arches don't provide vmalloc.h through the includes already included
in rtl8192su. This patch adds it.
Signed-off-by: NJeff Mahoney <jeffm@suse.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/staging/rtl8192su/r8192U_core.c

@@ -24,6 +24,7 @@
  * Jerry chuang <wlanfae@realtek.com>
  */
 
+#include <linux/vmalloc.h>
 
 #undef LOOP_TEST
 #undef DUMP_RX