firmware-imx: Use self-extractible helper

[Thomas: remove useless comment about looking in freescale-imx.mk.]

Signed-off-by: Jérôme Pouiller <jezz@sysmic.org>
Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/freescale-imx/firmware-imx/firmware-imx.mk

@@ -7,27 +7,18 @@
 FIRMWARE_IMX_VERSION = $(FREESCALE_IMX_VERSION)
 FIRMWARE_IMX_SITE = $(FREESCALE_IMX_SITE)
 FIRMWARE_IMX_SOURCE = firmware-imx-$(FIRMWARE_IMX_VERSION).bin
+
 FIRMWARE_IMX_LICENSE = Freescale Semiconductor Software License Agreement, \
 	Atheros license (ath6k)
-FIRMWARE_IMX_LICENSE_FILES = licenses/vpu/EULA licenses/ath6k/AR6102/License.txt
-# This is a legal minefield: the EULA specifies that
-# the Board Support Package includes software and hardware (sic!)
-# for which a separate license is needed...
+FIRMWARE_IMX_LICENSE_FILES = EULA licenses/vpu/EULA licenses/ath6k/AR6102/License.txt
 FIRMWARE_IMX_REDISTRIBUTE = NO
 
 FIRMWARE_IMX_BLOBS = ath6k sdma vpu
 
-# The archive is a shell-self-extractor of a bzipped tar. It happens
-# to extract in the correct directory (firmware-imx-x.y.z)
-# The --force makes sure it doesn't fail if the source dir already exists.
-# The --auto-accept skips the license check - not needed for us
-# because we have legal-info.
 define FIRMWARE_IMX_EXTRACT_CMDS
-	cd $(BUILD_DIR); \
-	sh $(DL_DIR)/$(FIRMWARE_IMX_SOURCE) --force --auto-accept
+	$(call FREESCALE_IMX_EXTRACT_HELPER,$(DL_DIR)/$(FIRMWARE_IMX_SOURCE))
 endef
 
-
 define FIRMWARE_IMX_INSTALL_TARGET_CMDS
 	mkdir -p $(TARGET_DIR)/lib/firmware
 	for blobdir in $(FIRMWARE_IMX_BLOBS); do \