driver-core: base: change to new flag variable

Replace EXTRA_CFLAGS with ccflags-y.
Signed-off-by: Nmatt mooney <mfm@muteddisk.com>
Acked-by: NWANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/base/Makefile

@@ -19,7 +19,5 @@ obj-$(CONFIG_MODULES)	+= module.o
 endif
 obj-$(CONFIG_SYS_HYPERVISOR) += hypervisor.o
 
-ifeq ($(CONFIG_DEBUG_DRIVER),y)
-EXTRA_CFLAGS += -DDEBUG
-endif
+ccflags-$(CONFIG_DEBUG_DRIVER) := -DDEBUG