dyndbg: replace kstrdup() + strchr() with kstrdup_and_replace()

Replace open coded functionalify of kstrdup_and_replace() with a call.

Link: https://lkml.kernel.org/r/20240213162741.3102810-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Jason Baron <jbaron@akamai.com>
Cc: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: andy-shev

lib/dynamic_debug.c

@@ -640,10 +640,9 @@ static int param_set_dyndbg_classnames(const char *instr, const struct kernel_pa
 	int cls_id, totct = 0;
 	bool wanted;
 
-	cl_str = tmp = kstrdup(instr, GFP_KERNEL);
-	p = strchr(cl_str, '\n');
-	if (p)
-		*p = '\0';
+	cl_str = tmp = kstrdup_and_replace(instr, '\n', '\0', GFP_KERNEL);
+	if (!tmp)
+		return -ENOMEM;
 
 	/* start with previously set state-bits, then modify */
 	curr_bits = old_bits = *dcp->bits;