Fix -Wsign-compare trouble

Mostly by changing to `unsigned` types where applicable, sometimes
`signed` types, and casting as a last resort.

Change-Id: I08895543ffb7a48058bcf91ef6500ca113f2d305
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/flashrom/+/30409
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Jacob Garber <jgarber1@ualberta.ca>
diff --git a/cli_classic.c b/cli_classic.c
index 0591bfe..b4112fd 100644
--- a/cli_classic.c
+++ b/cli_classic.c
@@ -507,7 +507,7 @@
 
 	for (j = 0; j < registered_master_count; j++) {
 		startchip = 0;
-		while (chipcount < ARRAY_SIZE(flashes)) {
+		while (chipcount < (int)ARRAY_SIZE(flashes)) {
 			startchip = probe_flash(&registered_masters[j], startchip, &flashes[chipcount], 0);
 			if (startchip == -1)
 				break;