isdn: change to new flag variable

Replace EXTRA_CFLAGS with ccflags-y.
Signed-off-by: matt mooney <mfm@muteddisk.com>
Acked-by: WANG Cong <xiyou.wangcong@gmail.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Michal Marek <mmarek@suse.cz>

drivers/isdn/hisax/Makefile

@@ -4,7 +4,7 @@
 
 # Define maximum number of cards
 
-EXTRA_CFLAGS      += -DHISAX_MAX_CARDS=$(CONFIG_HISAX_MAX_CARDS)
+ccflags-y      := -DHISAX_MAX_CARDS=$(CONFIG_HISAX_MAX_CARDS)
 
 obj-$(CONFIG_ISDN_DRV_HISAX)		+= hisax.o
 obj-$(CONFIG_HISAX_SEDLBAUER_CS)	+= sedlbauer_cs.o