bootstd: Use an enum for hunter numbers

Add more enum values so we can use these in the tests, instead of adding
comments. This makes it easier to adjust tests when new hunters are
added.

Signed-off-by: Simon Glass <sjg@chromium.org>

test/boot/bootstd_common.h

@@ -20,9 +20,15 @@
 #define TEST_VERSION		"U-Boot v2022.04-local2"
 #define TEST_VERNUM		0x00010002
 
+/* IDs for hunters, which is dependent on their binding order */
 enum {
-	MAX_HUNTER	= 9,
-	MMC_HUNTER	= 3,	/* ID of MMC hunter */
+	HUNTER_ETH	= 0,
+	HUNTER_SIMPLE_BUS,
+	HUNTER_MMC	= 3,
+	HUNTER_SCSI	= 6,
+	HUNTER_USB	= 8,
+	HUNTER_COUNT	= 10,
+	HUNTER_MAX	= HUNTER_COUNT - 1,
 };
 
 struct unit_test_state;