gianfar: Fix possible overrun and simplify interrupt name field creation

Space allocated for int_name_<foo> is insufficient for
maximal device name, expand it.

Code to create int_name_<foo> is obscure, simplify it
by using sprintf.

Found by looking for unnecessary \ line continuations.

Signed-off-by: Joe Perches <joe@perches.com>
Tested-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/freescale/gianfar.h b/drivers/net/ethernet/freescale/gianfar.h
index fc2488a..4c9f8d4 100644
--- a/drivers/net/ethernet/freescale/gianfar.h
+++ b/drivers/net/ethernet/freescale/gianfar.h
@@ -517,7 +517,7 @@
 #define RXFCB_PERR_MASK		0x000c
 #define RXFCB_PERR_BADL3	0x0008
 
-#define GFAR_INT_NAME_MAX	IFNAMSIZ + 4
+#define GFAR_INT_NAME_MAX	(IFNAMSIZ + 6)	/* '_g#_xx' */
 
 struct txbd8
 {