crash: add prefix for crash dumping messages

Add pr_fmt() to kernel/crash_core.c to add the module name to debugging
message printed as prefix.

And also add prefix 'crashkernel:' to two lines of message printing code
in kernel/crash_reserve.c. In kernel/crash_reserve.c, almost all
debugging messages have 'crashkernel:' prefix or there's keyword
crashkernel at the beginning or in the middle, adding pr_fmt() makes it
redundant.

Link: https://lkml.kernel.org/r/20240418035843.1562887-1-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: Baoquan He

kernel/crash_core.c

@@ -4,6 +4,8 @@
  * Copyright (C) 2002-2004 Eric Biederman  <ebiederm@xmission.com>
  */
 
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
 #include <linux/buildid.h>
 #include <linux/init.h>
 #include <linux/utsname.h>

kernel/crash_reserve.c

@@ -109,7 +109,7 @@ static int __init parse_crashkernel_mem(char *cmdline,
 
 		size = memparse(cur, &tmp);
 		if (cur == tmp) {
-			pr_warn("Memory value expected\n");
+			pr_warn("crashkernel: Memory value expected\n");
 			return -EINVAL;
 		}
 		cur = tmp;
@@ -132,7 +132,7 @@ static int __init parse_crashkernel_mem(char *cmdline,
 			cur++;
 			*crash_base = memparse(cur, &tmp);
 			if (cur == tmp) {
-				pr_warn("Memory value expected after '@'\n");
+				pr_warn("crahskernel: Memory value expected after '@'\n");
 				return -EINVAL;
 			}
 		}