char: 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>
Signed-off-by: Michal Marek <mmarek@suse.cz>
diff --git a/drivers/char/mwave/Makefile b/drivers/char/mwave/Makefile
index 26b4fce..efa6a82 100644
--- a/drivers/char/mwave/Makefile
+++ b/drivers/char/mwave/Makefile
@@ -9,7 +9,7 @@
 mwave-y := mwavedd.o smapi.o tp3780i.o 3780i.o
 
 # To have the mwave driver disable other uarts if necessary
-# EXTRA_CFLAGS += -DMWAVE_FUTZ_WITH_OTHER_DEVICES
+# ccflags-y := -DMWAVE_FUTZ_WITH_OTHER_DEVICES
 
 # To compile in lots (~20 KiB) of run-time enablable printk()s for debugging:
-ccflags-y := -DMW_TRACE
+ccflags-y += -DMW_TRACE