ARM: imx: mach-imx6ul: add imx6ulz support

imx6ulz is derived SoC from imx6ull.
Currently, the boards based on imx6ulz are correctly recognized only if
the compatible includes "fsl,imx6ull", while "fsl,imx6ulz" is ignored.

Signed-off-by: Pierluigi Passaro <pierluigi.p@variscite.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/mach-imx/mach-imx6ul.c

@@ -63,6 +63,7 @@ static void __init imx6ul_init_late(void)
 static const char * const imx6ul_dt_compat[] __initconst = {
 	"fsl,imx6ul",
 	"fsl,imx6ull",
+	"fsl,imx6ulz",
 	NULL,
 };