package/freescale-imx: Remove imx6s from has_vpu list

package/freescale-imx: Remove imx6s from has_vpu list

According to imx-vpu-5.4.37/Makefile, line 6:

	INCLUDE_LIST:= IMX27ADS IMX51 IMX53 IMX6Q

imx6s is not supported by the imx-vpu package. Its install target,
guarded by

	ifeq ($(PLATFORM), $(findstring $(PLATFORM), $(INCLUDE_LIST)))

does nothing, causing a build error later on in the imx-vpuwrap package

checking for vpu_lib.h... no
configure: error: lib_vpu is required, consider installing imx-lib

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Reviewed-by: Gary Bisson <gary.bisson@boundarydevices.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>