dtc: Fix signedness comparisons warnings: reservednum

With -Wsign-compare, compilers warn about a mismatching signedness
in comparisons in code using the "reservednum" variable.

There is obviously little sense in having a negative number of reserved
memory entries, so let's make this variable and all its users unsigned.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Message-Id: <20210611171040.25524-6-andre.przywara@arm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

dtc.c

@@ -12,7 +12,7 @@
  * Command line options
  */
 int quiet;		/* Level of quietness */
-int reservenum;		/* Number of memory reservation slots */
+unsigned int reservenum;/* Number of memory reservation slots */
 int minsize;		/* Minimum blob size */
 int padsize;		/* Additional padding to blob */
 int alignsize;		/* Additional padding to blob accroding to the alignsize */
@@ -197,7 +197,7 @@ int main(int argc, char *argv[])
 			depname = optarg;
 			break;
 		case 'R':
-			reservenum = strtol(optarg, NULL, 0);
+			reservenum = strtoul(optarg, NULL, 0);
 			break;
 		case 'S':
 			minsize = strtol(optarg, NULL, 0);

dtc.h

@@ -35,7 +35,7 @@
  * Command line options
  */
 extern int quiet;		/* Level of quietness */
-extern int reservenum;		/* Number of memory reservation slots */
+extern unsigned int reservenum;	/* Number of memory reservation slots */
 extern int minsize;		/* Minimum blob size */
 extern int padsize;		/* Additional padding to blob */
 extern int alignsize;		/* Additional padding to blob accroding to the alignsize */

flattree.c

@@ -295,7 +295,7 @@ static struct data flatten_reserve_list(struct reserve_info *reservelist,
 {
 	struct reserve_info *re;
 	struct data d = empty_data;
-	int    j;
+	unsigned int j;
 
 	for (re = reservelist; re; re = re->next) {
 		d = data_append_re(d, re->address, re->size);