cxgb4: Fix build error due to missing linux/vmalloc.h include.

Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/chelsio/cxgb4/cxgb4.h

@@ -43,6 +43,7 @@
 #include <linux/pci.h>
 #include <linux/spinlock.h>
 #include <linux/timer.h>
+#include <linux/vmalloc.h>
 #include <asm/io.h>
 #include "cxgb4_uld.h"
 #include "t4_hw.h"