watchdog: handle comma separated nmi_watchdog command line

Per the document, the kernel can accept comma separated command line like
nmi_watchdog=nopanic,0.  However, the code doesn't really handle it.  Fix
the kernel to handle it properly.

Link: https://lkml.kernel.org/r/20240430060236.1878002-1-song@kernel.org
Signed-off-by: Song Liu <song@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: liu-song-6

kernel/watchdog.c

@@ -71,6 +71,7 @@ void __init hardlockup_detector_disable(void)
 
 static int __init hardlockup_panic_setup(char *str)
 {
+next:
 	if (!strncmp(str, "panic", 5))
 		hardlockup_panic = 1;
 	else if (!strncmp(str, "nopanic", 7))
@@ -79,6 +80,12 @@ static int __init hardlockup_panic_setup(char *str)
 		watchdog_hardlockup_user_enabled = 0;
 	else if (!strncmp(str, "1", 1))
 		watchdog_hardlockup_user_enabled = 1;
+	while (*(str++)) {
+		if (*str == ',') {
+			str++;
+			goto next;
+		}
+	}
 	return 1;
 }
 __setup("nmi_watchdog=", hardlockup_panic_setup);