pitx-imx8m: fiw hardware variant check

Detection of HW variant before iomux fixup for L120 failed. As a result
iomux fixup is skipped. Fix this.
Signed-off-by: Thomas Schaefer <thomas.schaefer@kontron.com>

board/kontron/pitx-imx8m/pitx-imx8m.c

@@ -547,8 +547,7 @@ int misc_init_r(void)
 	gpio_direction_output(USBHUB_RESET, 1);
 
 	hw_rev = get_hw_rev();
-	/* check if hw variant is L120 (7) */
-	if (hw_rev == 7) {
+	if (!strcmp(hw_variants[hw_rev], "L120")) {
 		int nodeoffset;
 		void *fdt = map_sysmem((ulong)gd->fdt_blob, 0);