scripts/dtc: Update to upstream version v1.6.1-66-gabbd523bae6e

This adds the following commits from upstream:

abbd523bae6e pylibfdt: Work-around SWIG limitations with flexible arrays
a41509bea3e7 libfdt: Replace deprecated 0-length arrays with proper flexible arrays
2cd89f862cdb dtc: Warning rather than error on possible truncation of cell values

Reviewed-by: Kees Cook <[e-mail]>
Link: https://lore.kernel.org/all/[e-mail]/
Signed-off-by: Rob Herring <[e-mail]>

scripts/dtc/dtc-parser.y

···
 				 * within the mask to one (i.e. | in the
 				 * mask), all bits are one.
 				 */
-				if (($2 > mask) && (($2 | mask) != -1ULL))
-					ERROR(&@2, "Value out of range for"
-					      " %d-bit array element", $1.bits);
+				if (($2 > mask) && (($2 | mask) != -1ULL)) {
+					char *loc = srcpos_string(&@2);
+					fprintf(stderr,
+						"WARNING: %s: Value 0x%016" PRIx64
+						" truncated to 0x%0*" PRIx64 "\n",
+						loc, $2, $1.bits / 4, ($2 & mask));
+					free(loc);
+				}
 			}
 
 			$$.data = data_append_integer($1.data, $2, $1.bits);

scripts/dtc/libfdt/fdt.h

···
 
 struct fdt_node_header {
 	fdt32_t tag;
-	char name[0];
+	char name[];
 };
 
 struct fdt_property {
 	fdt32_t tag;
 	fdt32_t len;
 	fdt32_t nameoff;
-	char data[0];
+	char data[];
 };
 
 #endif /* !__ASSEMBLY */

scripts/dtc/version_gen.h

···
-#define DTC_VERSION "DTC 1.6.1-g55778a03"
+#define DTC_VERSION "DTC 1.6.1-gabbd523b"