kallsyms: use kmalloc_array() instead of kmalloc()

Replace kmalloc(sizeof(*stat) * 2, GFP_KERNEL) with kmalloc_array(2,
sizeof(*stat), GFP_KERNEL) to prevent potential overflow, as recommended
in Documentation/process/deprecated.rst.

Link: https://lkml.kernel.org/r/20250926075053.25615-1-chandna.linuxkernel@gmail.com
Signed-off-by: Sahil Chandna <chandna.linuxkernel@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: David Hunter <david.hunter.linux@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: Sahil Chandna

kernel/kallsyms_selftest.c

@@ -264,7 +264,7 @@ static int test_kallsyms_basic_function(void)
 	char namebuf[KSYM_NAME_LEN];
 	struct test_stat *stat, *stat2;
 
-	stat = kmalloc(sizeof(*stat) * 2, GFP_KERNEL);
+	stat = kmalloc_array(2, sizeof(*stat), GFP_KERNEL);
 	if (!stat)
 		return -ENOMEM;
 	stat2 = stat + 1;